Academic literature on the topic 'Mixed species plantation'

Anbarashan M, Padmavathy A, Alexandar R. 2017. Short Communication: Survival and growth of mono and mixed species plantations on the Coromandel coast of India. Asian J For 1: 70-76. There exists very little information on the growth of autochthonous tree species autochthonousin the tropics and on the experiences in conducting mono and mixed species plantations. The aim of this study was to compare the variation in growth parameter between the mixed species plantation and mono species plantation. The growth, survival, and height of 82 autochthonous mixed species plantations were compared with Casuarina equisetifolia, an exotic species broadly planted in this region after over a decade (2006 to 2016). In the mixed species plantation, seven species showed 100 % survival rate and 19 species were not survived after 10-year intervals. In the mono species plantation, Casuarina equisetifolia had 92 % of the survival rate. When it is compared to the mono plantation, the growth rate of mixed species plantation showed highly significant differences (P < 0: 05) values. Simple linear regression between annual girth increment and height produced very strong positive relations (R2 0.759). Plantations of Casuarina equisetifolia seem to be well adapted to the coastal region. On the other hand, mixed plantation with autochthonous species would contribute more to sustainable management because they provide a greater range of ecological goods and ecosystem services than the single species plantations.

Eucalyptus plantations harbor great potential for supporting ecosystem services, but this prospect is weakened under long-term traditional silviculture regimes. To reform these traditional silviculture regimes, we carried out a long-term Eucalyptus eco-silviculture experiment. However, the derived benefits and mechanisms that arise in mixed species stands under the eco-silviculture regime are not fully understood. Here, we evaluated tree carbon storage (TCS), understory vegetation carbon storage (UCS), floor litter carbon storage (FLCS), soil organic carbon storage (SOCS), and ecosystem carbon storage (ECS) in seven-year-old mono-specific plantations of a Eucalyptus hybrid (E. urophylla × E. grandis) and Castanopsis hystrix, as well as mixed plantations of these two trees under an eco-silviculture regime in southern China. The results showed that the tree height, diameter at breast height (DBH), volume, and biomass of eucalypt trees and C. hystrix in the mixed plantation were significantly higher than that of the trees in the corresponding single-species plantations. The mixed-species plantation had the largest TCS (84.33 Mg ha−1), FLCS (4.34 Mg ha−1), and ECS (313.31 Mg ha−1), as well as a higher SOCS (233.98 Mg ha−1), but the lowest UCS (0.96 Mg ha−1), among the three plantation types. The mixture effects analysis revealed significant synergistic effects (non-additive effect, NAE > 0) on TCS, SOCS, and ECS, and significant antagonistic effects (NAE < 0) on UCS. These synergistic effects were mainly due to the complementary ecological niches of the two species in the mixed-species plantation, which could potentially enable them to maximize the use of local resources, and to increase stand productivity and litter production. These results imply that beyond the gains in timber production obtained by having both Eucalyptus and C. hystrix trees growing in the same plantation stand, such mixed-species plantations enhance carbon sequestration to a greater extent than mono-specific plantations of either Eucalyptus or C.hystrix trees. In conclusion, we suggest planting mixed plantations of species with complementary ecological niches under an eco-silviculture regime, to effectively resolve the contradiction between timber production and ecosystem services, and, thereby, also promote the sustainable development of Eucalyptus plantations.

Reforestation plays an important role in the carbon cycle and climate change. However, knowledge of ecosystem carbon sequestration through reforestation with mixed species is limited. Especially in dry hot valley of the Jinsha River, no studies cover total ecosystem carbon sequestration level in mature mixed plantations for a limited area of mixed plantations and difficulty in the sampling of plant roots and deep soil. In this study, carbon sequestration of seven mixed plantations of different ages in dry hot valley of the Jinsha River was investigated with analogous sites method. The results are as follows: 1) Deep soil organic carbon (SOC) storage significantly increased with stand age (p = 0.025), possibly due to fine root exudates and dissolved organic carbon transportation into deep soil and retention. 2) Total biomass carbon storage in the 30-year-old mixed plantation was 77.78 t C ha−1, 54 times reference wasteland and 9 times reference natural recovery shrub-grassland. However, total biomass carbon storage of 30-year-old mixed plantation was insignificantly lower than that of reference natural forest (p = 0.429). After 30 years of reforestation, plantation biomass carbon storage recovered to reference level, and its sequestration rate was 2.54 t C ha−1 yr−1. 3) The total ecosystem carbon storage of 30-year-old mixed plantation was 185.50 t C ha−1, 2.38 times reference wasteland, 2.29 times reference natural recovery shrub grassland, and 29% lower than reference natural forest. It indicated that niche complementary, good stand structure, and characteristics of dominant species Leucaena leucocephala in mixed plantations facilitate more rapid carbon sequestration, especially biomass carbon in the dry hot valley.

The conversion of natural forest to agroforestry plantations and annual cropping systems alters the soil habitat and food resources for biota, including earthworms. Native earthworm species may disappear whereas exotic species with greater tolerance of disturbance and less niche specialisation may thrive. The objective of the study was to compare the earthworm diversity in managed forest and agroforestry systems, which were cultivated for mixed plantation and annual crop production on Mount Gede, Indonesia. All the habitats in the study area were impacted by humans. The forest habitat was a managed forest, with a permanent tree cover, whereas mixed plantation had a partial shrub cover. Meanwhile, homogenous plantation was cultivated with annual crops. Among 3787 individuals collected during July–October 2012, five Oriental earthworm species were identified in the soil communities of Mount Gede: Drawida nepalensis, Notoscolex javanica, Pheretima pura-group, Polypheretima moelleri, and Polypheretima sempolensis. Also, 18 species were found that are reported to be non-Oriental in origin. Anthropogenic disturbance of forests on Mount Gede, due to conversion into plantations, alters the earthworm environment by increasing soil water content, temperature and total phosphorous content, while decreasing organic carbon. N. javanica was the only native species to survive this deforestation, while the exotic Ocnerodrilus occidentalis and Pontoscolex corethrurus thrived, becoming the eudominant species. From the forest area to the mixed and homogenous plantations, the predicted decreasing diversity is evidenced by the lowering trend of Shannon’s diversity index. In conclusion, the land-use change into mixed plantations and annual croplands has reduced earthworm diversity in this region of Mount Gede, Indonesia.

Background and Objectives: The stable stand structure of mixed plantations is the basis of giving full play to forest ecological function and benefit. However, the monocultural Eucalyptus plantations with large-scale and successive planting that caused ecological problems such as reduced species diversity and loss of soil nutrients have presented to be unstable and vulnerable, especially in typhoon-prone areas. The objective of this study was to evaluate the nonspatial structure difference and the stand stability of pure and mixed-Eucalyptus forests, to find out the best mixed pattern of Eucalyptus forests with the most stability in typhoon-prone areas. Materials and Methods: In this study, we randomly investigated eight plots of 30 m × 30 m in pure and mixed-Eucalyptus (Eucalyptus urophylla S. T. Blake × E. grandis W. Hill) plantations of different tree species (Neolamarckia cadamba (Roxb.) Bosser, Acacia mangium Willd., and Pinus elliottii var. Elliottii Engelm. × P. caribaea Morelet) on growth status, characterized and compared the distribution of nonspatial structure of the monoculture and mixtures, and evaluated the stand quality and stability from eight indexes of the nonspatial structure, including preservation rate, stand density, height, diameter, stem form, degree of stem inclination, tree-species composition, and age structure. Results: Eucalyptus surviving in the mixed plantation of Eucalyptus and A. mangium (EA) and in the mixed plantation of Eucalyptus and P. elliottii × P. caribaea (EP) were 5.0% and 7.6% greater than those in pure Eucalyptus plantation (EE), respectively, while only the stand preservation rate of EA was greater (+2.9%) than that of the pure Eucalyptus plantation. The proportions of all mixtures in the height class greater than 7 m were fewer than that of EE. The proportions of EA and mixed plantation of Eucalyptus and N. cadamba (EN) in the diameter class greater than 7 m were 10.6% and 7.8%, respectively, more than that of EE. EN had the highest ratio of branching visibly (41.0%), EA had the highest ratio of inclined stems (8.1%), and EP had the most straight and complete stem form (68.7%). The stand stability of the mixed plantation of Eucalyptus and A. mangium presented to be optimal, as its subordinate function value (0.76) and state value (ω = 0.61) of real stand were the largest. Conclusions: A. mangium is a superior tree species to mix with Eucalyptus for a more stable stand structure in the early growth stage to approach an evident and immense stability and resistance, which is of great significance for the forest restoration of Eucalyptus in response to extreme climate and forest management.

Phosphorus (P) is a key limiting nutrient in subtropical forests and mixed forests with broadleaved species have been expected to stimulate P cycling, compared to pure conifer plantations. However, the mixture effect of Chinese fir (Cunninghamia lanceolata (Lamb.) Hook.) and broadleaved species on rhizosphere soil and coniferous tree P dynamics is unclear. In our study, eight plots of a single species of a Chinese fir plantation (pure plantation, PP) and eight mixed plantations (mixed plantation, MP) with broadleaved tree species (Michelia macclurei Dandy in Hunan Province or Schima superba Gardn. et Champ. in Fujian Province) were selected in subtropical China. Six P fractions in the rhizosphere and bulk soils were analyzed by a modified Hedley P fractionation method. Phosphorus fractions and nitrogen (N) concentrations in different root orders, different age fresh needles and twigs, and needle and twig litter of Chinese fir were measured. Our results showed that available P, slowly released P, occluded P, and the total extractable P in rhizosphere soil were significantly higher in MP than PP (p < 0.05). In contrast, P and N concentrations in the transportive roots and two-year old needles were generally higher in PP than MP. Meanwhile, the slowly released P, occluded P, total extractable P, and residual P in rhizosphere soil were negatively correlated with P concentrations in young (absorptive and transportive roots, one- and two-year old needles) but not old tissues (storative roots, three-year old needles and litters). In conclusion, mixture may increase soil P availability through the rhizosphere effect, but can decrease P and N concentration of Chinese fir tissues by competition between Chinese fir and broadleaved species. Clearly, the mixture effect may differ in soil and plant nutrients, and this issue needs be taken into consideration when converting a pure conifer plantation into a mixed-species forest.

Many survival and ecological problems have emerged in Pinus yunnanensis pure pine forest plantations that are usually assumed to be solved by creating mixed plantations. On this basis, we determined the physicochemical properties and enzyme activities of three soil layers in pure and three types of mixed P. yunnanensis plantation stands (admixed species: Alnus nepalensis, Celtis tetrandra, and Quercus acutissima) in Southwest China. We used one-way ANOVA with Tukey’s test to analyze the effects of plantation type and depth on the soil’s properties and variations among different depths. Principal component analysis combined with cluster analysis was used to evaluate the soil quality of different forest types comprehensively. The results showed that the stand with a mixing proportion of 2:1 of P. yunnanensis and A. nepalensis, C. tetrandra, and Q. acutissima had higher total porosity, moisture content, total nitrogen, available phosphorus, total phosphorus, sucrase, urease, and catalase enzyme activities than other proportions of mixed forest and P. yunnanensis pine pure forest. In general, the mixed P. yunnanensis plantation could improve the soil quality, especially its chemical properties and enzymes. This study provides a basis for creating a mixed-mode of P. yunnanensis and other tree species that can not only improve the economy of forest land but also enhance the ecological value.

Base cation transfer from stemflow is an important process for nutrient transfer and plays a key role in maintaining the balance of soil nutrient pools. To research the differences of stemflow chemistry in mixed plantations, we conducted a continuous field experiment in the rainy zone of Western China from December 2016 to November 2017. Three representative mixed plantations, including a conifer–broadleaved mixed plantation, a deciduous broadleaved mixed plantation and a multispecies mixed plantation, were selected to investigate the concentration and flux characteristics of K+, Na+, Ca2+ and Mg2+ in stemflow. The results showed that: (1) the K+, Na+, Ca2+ and Mg2+ fluxes ranged from 1.75 to 2.44 kg ha−1 year−1, 0.14 to 0.24 kg ha−1 year−1, 1.25 to 2.11 kg ha−1 year−1, and 0.40 to 0.60 kg ha−1 year−1 in these mixed plantations during the one-year observation, and the annual or seasonal (i.e., rainy or dry season) base cation fluxes in the stemflow varied slightly with the plantation types; (2) broadleaved trees had a higher average stemflow base cation contribution rate and flux-based enrichment ratio than coniferous trees, and the enrichment ratios showed a decreasing tendency with increasing trunk diameter; (3) the stemflow base cation concentration was higher in the dry season, while flux was observed to be higher in the rainy season. These results suggested that increasing the proportion of broadleaved species in mixed plantations might improve soil nutrient content and benefit material cycling in subtropical forest ecosystems.

The soil microbial community structure is critical to the cycling of carbon and nitrogen in forest soils. As afforestation practices increasingly promote different functional traits of tree species, it has become critical to understand how they influence soil microbial community structures, which directly influence soil biogeochemical processes. We used fungi ITS and bacteria 16S rDNA to investigate soil microbial community structures in three monoculture plantations consisting of a non-native evergreen conifer (Pinus sibirica), a native deciduous conifer (Larix gmelinii), and a native deciduous angiosperm (Betula platyphylla) and compared them with two 1:1 mixed-species plantations (P. sibirica and L. gmelinii, P. sibirica and B. platyphylla). The fungal community structure of the conifer–angiosperm mixed plantation was similar to that of the non-native evergreen conifer, and the bacterial community structure was similar to that of the angiosperm monoculture plantation. Fungal communities were strongly related to tree species, but bacterial communities were strongly related to soil nitrogen. The co-occurrence networks were more robust in the mixed plantations, and the microbial structures associated with soil carbon and nitrogen were significantly increased. Our results provide a comparative study of the soil microbial ecology in response to afforestation of species with different functional traits and enhance the understanding of factors controlling the soil microbial community structure.

Although the advantages of multi-species plantations over single-species plantations have been widely recognized, the mechanisms driving these advantages remain unclear. In this study, we compared stand biomass, litter production and quality, soil properties, soil microbial community, and functions in a Pinus massoniana Lamb. and Castanopsis hystrix Miq. mixed plantation and their corresponding mono-specific plantations after 34 years afforestation in subtropical China. The results have shown that a coniferous-broadleaf mixture created significantly positive effects on stand biomass, litter production, soil microbial biomass, and activities. Firstly, the tree, shrub and herb biomass, and litter production were significantly higher in the coniferous-broadleaf mixed plantation. Secondly, although the concentrations of soil organic carbon (SOC) and total nitrogen (TN) were lower in the mixed stand, the concentrations of soil microbial biomass carbon (MBC), and nitrogen (MBN), along with MBC-to-SOC and MBN-to-TN ratio, were significantly higher in mixed stands with markedly positive admixing effects. We also found higher carbon source utilization ability and β−1, 4−N−acetylglucosaminidase, urease and acid phosphatase activities in mixed stands compared with the mono-species stands. Our results highlight that establishment of coniferous-broadleaf mixed forests may be a good management practice as coniferous-broadleaf mixture could accumulate higher stand biomass and return more litter, resulting in increasing soil microbial biomass and related functions for the long term in subtropical China.

Mixed-species plantations of eucalypts and acacias have the potential to improve stand productivity over that of respective monocultures through the facilitative effect of nitrogen-fixation by acacias, and increased resource capture through above- and belowground stratification. However, growth in mixed-species plantations may not be improved compared to that of monocultures when competitive interactions outweigh the effects of improved nutrient availability and resource capture. Careful selection of sites and species is therefore critical to successfully improving stand productivity using mixed-species plantations. This study set out to examine some of the processes and interactions that occur in mixed-species plantations, and the effect nutrient and water availability can have on the growth of mixtures. In three out of four mixed-species field trials examined in this study, growth was not increased in mixtures compared to monocultures. However, in the fourth field trial, heights, diameters, stand volume and aboveground biomass were higher in mixtures of E. globulus and A. mearnsii from 3-4 years after planting. The range in outcomes from mixing species in these four trials shows that a fundamental understanding of the underlying processes is required to enable a greater predictive capacity for the circumstances under which mixtures will be successful. Therefore the growth dynamics, processes and interactions were examined in the mixtures of E. globulus and A. mearnsii. The difference in productivity between mixtures and monocultures in this trial increased with time up to age 11 years, when 1:1 mixtures contained twice the aboveground biomass of E. globulus monocultures. The positive growth response of trees in mixture compared to monocultures was the result of accelerated rates of nutrient cycling, a shift in C allocation and reductions in light competition through canopy stratification. Nitrogen contents of foliage and soil clearly showed that A. mearnsii influenced the N dynamics in this trial. If these changes in N contents were due to N fixation by A. mearnsii, then about 51 and 86 kg N ha-1 yr-1 was fixed in the 1:1 mixtures and A. mearnsii monocultures, respectively. Nitrogen fixation was also examined using the natural abundance method. The delta15N values of foliage collected at 10 years were grouped according to the mycorrhizal status of the host plant. Therefore the discrimination of 15N during transfer from mycorrhizae to the host plant appeared to vary with mycorrhizal status, and the natural abundance of 15N was not used to quantify N fixation. Rates of N and P cycling in litterfall were significantly higher in stands containing at least 25% A. mearnsii (more than 31 kg N ha-1 yr-1 and more than 0.68 kg P ha-1 yr-1) compared to E. globulus monocultures (24 kg N ha-1 yr-1 and 0.45 kg P ha-1 yr-1). Rates of litter decomposition and N and P release were about twice as high in 1:1 mixtures compared to E. globulus monocultures and were even higher in A. mearnsii monocultures. It is therefore important to select N-fixing species that are capable of cycling nutrients quickly between the plant and soil, and that have readily decomposable litter. The total belowground C allocation was not significantly different between mixtures and monocultures (14 to 16 Mg C ha-1 yr-1). However, since aboveground net primary production was greater in 1:1 mixtures, the changes in nutrient availability appears to have increased total productivity (both above- and belowground), and reduced the proportion of C allocated belowground in mixtures compared to E. globulus monocultures. In a pot trial containing mixtures of E. globulus and A. mearnsii both species grew larger in mixture than in monoculture at low N levels, and mixtures were more productive than monocultures. However, at high N levels, E. globulus suppressed A. mearnsii and mixtures were less productive than E. globulus monocultures. Similar effects were found for high and low levels of P. Therefore resource availability can have a strong influence on the interactions and growth of mixtures. The productivity of mixtures may only be increased on sites where the resource for which competition is reduced in mixture is a major limiting growth resource. For example, if N is not a limiting growth factor then an increase in N availability from N-fixation may not increase growth, and the N-fixing species may compete for other resources such as soil P, moisture or light. This study has shown that mixtures containing a N-fixing trees and a non-N-fixing trees can be more productive than monocultures, but that this increase in productivity will only occur on certain sites. Examination of the growth, interactions and processes that occurred in mixtures in this study provide useful information that can aid the selection of species combinations and sites.

The high cost of restoring tropical forests is one of the greatest obstacle to achieving large-scale restoration. To overcome this barrier, we developed and implemented mixed plantations intercropping Eucalyptus with a high diversity of native tree species. The aim was to create favorable conditions for the regeneration of native species while simultaneously obtaining economic return from the exploitation of Eucalyptus as a commercial pioneer species. The use of Eucalyptus in this system is temporary and it shall be replaced by additional native species after it is harvested. In this research, we covered the main aspects and approaches of the effects of competition on tree growth using data from our restoration experiments. The objective of this research was to test the ecological viability of plantations that temporarily mix Eucalyptus spp. and a high diversity of native tree species during the initial phases of forest restoration as a strategy to offset implementation and maintenance costs. This alternative is investigated with a focus on the consequences of ecological interactions on tree survival and growth in three experiments implemented in the Atlantic Forest of Northeastern and Southeastern Brazil. We compared stands of native trees intercropped with Eucalyptus, traditional restoration plantations, and Eucalyptus monocultures. The thesis is structured in three main parts in which we focus in how the mixtures function compared to restoration plantations and Eucalyptus monocultures. We used forest inventories to understand the effects of competition and assessed ecophysiological parameters to provide insights about the mechanisms that affect tree growth when trees compete for water, light and nutrients. In the first part of the study, we showed that mixed plantations effectively combined high wood yield and tree diversity; that Eucalyptus grew larger in mixtures with native species than in monocultures; that native tree species grew less in mixtures with Eucalyptus; and that the mixing effect was stronger for fast- and intermediate-growing native species. In the second part, we found that mixtures consumed less water than monocultures; that Eucalyptus reduced the hydraulic performance of a fast-growing native species; and that tree growth was influenced by changes in the ecophysiology of water use. In the last part, we showed that a high diversity of nitrogen-fixing native trees facilitated Eucalyptus growth; that Eucalyptus had ~30% higher wood N concentration in mixtures; that native trees growth was not limited by nutrient competition with Eucalyptus; that Eucalyptus may benefit from increased light availability in mixed plantations; and that native species plots intercepted more sunlight than mixtures or Eucalyptus stands. This research has a strong interface between restoration science and practice, and contributed to the development of new ways to restore the tropical forests by allying restoration and production under the ecological and economic perspectives. Our findings indicate how to advance into the future, starting from the current state of art towards forest restoration systems that minimize competition and maximize growth, as an emergent promising alternative to finance tropical forest restoration and overcome the economic barrier that still holds large-scale restoration. This research may be used as a basis to continue adapting silviculture for different regions and forest ecosystems. Looking further into the future, these mixtures may also represent the starting point of a new silvicultural model that brings together production and conservation. The information available may be used by scientists, decision-makers, planners and restorationists to advance in the science and practice of restoration and silviculture in the tropics.
O alto custo de se restaurar as florestas tropicais são um dos maiores obstáculos para se atingir a restauração em larga escala. Para superar essa barreira, nós desenvolvemos e implantamos plantações mistas que intercalam Eucalyptus e uma alta diversidade de espécies arbóreas nativas. O objetivo é criar condições favoráveis para a regeneração das espécies nativas e, ao mesmo tempo, obter retorno econômico da exploração de eucalipto como uma espécie pioneira comercial. O uso do eucalipto nesse sistema é temporário e ele deve ser substituído por espécies nativa adicionais após ser colhido. Nessa pesquisa, nós cobrimos os principais aspectos e abordagens relacionados aos efeitos da competição sobre o crescimento arbóreo utilizando dados dos nossos experimentos. O objetivo dessa pesquisa foi testar a viabilidade ecológica de plantios que consorciam temporariamente eucalipto e uma alta diversidade de espécies arbóreas nativas durante as fases iniciais da restauração ecológica como uma estratégia para compensar parte dos custos de implantação e manutenção. Essa alternativa é investigada com foco nas consequências das interações ecológicas sobre a sobrevivência e o crescimento das árvores em três experimentos implantados na Mata Atlântica do nordeste e sudeste do Brasil. Nós implantamos e comparamos talhões de espécies nativas intercaladas com eucalipto, plantios de restauração tradicionais e monocultivos de eucalipto. A tese é estruturada em três partes principais com foco em como os plantios mistos funcionam em comparação a plantios de restauração e monocultivos de eucalipto. Nós utilizamos inventários florestais para entender os efeitos da competição e estimamos parâmetros ecofisiológicos para investigar os mecanismos que afetam o crescimento arbóreo quando as árvores competem por água, luz e nutrientes. Na primeira parte do estudo, nó mostramos que os plantios mistos combinaram efetivamente alta produção de madeira com diversidade arbórea; que eucalipto cresceu mais em plantios mistos do que em monocultivos; que espécies nativas cresceram menos em consórcio com eucalipto; e que o efeito do consórcio foi maior para espécies de crescimento rápido e intermediário. Na segunda parte, mostramos que plantios mistos consumiram menos água do que monocultivos; que Eucalyptus reduziu a performance hidráulica de uma espécie nativa de rápido crescimento; e que o crescimento das árvores foi influenciado por mudanças na ecofisiologia do uso da água. Na última parte, nós mostramos que uma alta diversidade de espécies arbóreas fixadoras de nitrogênio facilitaram o crescimento de Eucalyptus; que Eucalyptus teve concentração de N ~30% mais alta na madeira, em plantios mistos; que o crescimento de árvores nativas não foi limitado pela competição por nutrientes com eucalipto; que eucalipto pode se beneficiar de maior disponibilidade de luz em plantios mistos; e que parcelas de espécies nativas interceptaram mais luz do que plantios mistos ou monocultivos de eucalipto. Essa pesquisa tem uma forte interface entre a ciência e a prática da restauração, e contribuiu para o desenvolvimento de novas maneiras de se restaurar as florestas tropicais por meio da aliança entre restauração e produção sob as perspectivas ecológica e econômica. Nossas descobertas indicam como avançar no futuro, a partir do estado da arte atual, em direção a sistemas de restauração florestal que minimizem a competição e maximizem o crescimento, como uma alternativa emergente e promissora para compensar os custos da restauração e superar a barreira econômica que ainda impede a restauração em larga escala. Essa pesquisa pode ser utilizada como uma base para se continuar adaptando a silvicultura a diferentes regiões e ecossistemas florestais. Olhando para o futuro mais distante, esses plantios mistos podem também representar um ponto inicial de um novo modelo de silvicultura que alia produção e conservação. A informação disponibilidade deve ser utilizada por cientistas, tomadores de decisão, planejadores e restauradores para avançar com a ciência e a prática da restauração e da silvicultura nos trópicos.

The mixed plantation of valuable species with nitrogen-fixing species can increase the productivity levels for the target species. So, in 1998, in the framework of the Project PRAXIS XXI – 3/3.2/Flor/2127/95, a mixture plantation trial with valuable broadleaved tree species: wild cherry (Prunus avium L.), red oak (Quercus rubra L.) and sweet chestnut (Castanea sativa Mill.) with the accessory species black locust, was established in a substitutive or replacement series design in Vimioso (Latitude 41º34'12''N; Longitude 6º30'7''W and altitude 700 m), before the publication of decree law 565/99. A completely random experimental de-sign of 30 permanent sample plots with 10 treatments and 3 replications was adopted and two types of mixtures were considered (alternating lines of the objective-species with black locust and objective-species alternating with black locust in the line). The aim of this study is to evaluate the benefits for the objective-species when mixed with a nitrogen fixing species. In the dormancy of 2016/2017 the trial was measured but we consider only the treatments with wild cherry and red oak as objective-species and the black locust as accessory species. The plantations were assessed according to the survival rate, height and diameter growth, considering the dendrometric variables: height, diameter, coefficient of stability, and relative yield and relative yield total. Logistic regression was used to model the survival of the objective species in the mixture. The Wald Z test used showed that wild cherry is associated to a high probability of survival (64-75%) both in the pure treatment and in those mixed with black locust. For the red oak, the test indicated a low probability of survival mainly because of the breakdown verified in the establishment phase (46-55% survival at 10 years old) worsen by the strong black frost in the spring of 2010. Currently the survival of red oak ranges from 35 to 54%. For each species, the growth was compared among the different treatments using the least significant difference test (LSD). The treatment line-by-line of the wild cherry with black locust showed positive response in all assessment criteria, mainly survival rate (75%), the relative yield and the relative yield total, and height growth. The other mixtures presented either negative or non-significant results. The facilitation/complementarity effect promoted by the accessory species is evident only in the wild cherry.
A plantação mista de espécies produtoras de madeiras nobres com espécies fixadoras de azoto pode incrementar a sua produtividade. Assim, em 1998, no âmbito do Projeto PRAXIS XXI – 3/3.2/Flor/2127/95, foi estabelecido um ensaio de consociação de folhosas nobres: cerejeira brava (Prunus avium L.), carvalho americano (Quercus rubra L.) e castanheiro bravo (Castanea sativa Mill.) com a espécie acessória robínia falsa-acácia, numa série substitutiva, em Vimioso (Latitude 41º34'12''N; Longitude 6º30'7''W e altitude 700 m), antes da publicação do Decreto-Lei 565/99. O ensaio foi delineado em 30 parcelas de estudo permanentes estruturadas num desenho experimental aleatorizado com dez tratamentos e três repetições, sendo testados dois tipos de mistura (espécie objetivo ou principal alternada linha a linha com robínia e espécie objetivo alternada pé-a-pé com robínia). O objetivo deste estudo é avaliar os ganhos das espécies principais em mistura com uma fixadora de azoto. O ensaio foi medido novamente no repouso vegetativo de 2016/2017 mas neste estudo apenas se consideram os tratamentos com cerejeira e carvalho americano como espécies principais e a robínia como espécie acessória. O ensaio foi avaliado em termos de sobrevivência e crescimento em altura e em diâmetro. Para tal consideraram-se as seguintes variáveis: altura total, diâmetro, coeficiente de estabilidade e produção relativa e produção relativa total. Foi usada a regressão logística para modelar a sobrevivência das espécies principais na mistura. A aplicação do teste Wald Z mostrou que a cerejeira está associada a uma elevada probabilidade de sobrevivência (64-75%) tanto no tratamento puro como nos mistos com robínia. O mesmo teste demonstrou que o carvalho americano está associado a uma baixa probabilidade de sobreviver devido, principalmente, ao insucesso verificado na fase de instalação (sobrevivência 46 - 55% até aos 10 anos) agravada pela forte geada negra que ocorreu na primavera de 2010. Atualmente a sobrevivência do carvalho americano varia de 35 a 54 %. Comparou-se o crescimento para cada espécie, entre os diferentes tratamentos, usando o teste das diferenças mínimas significativas (LSD). O tratamento correspondente à mistura linha a linha com robínia mostrou uma resposta positiva em todos os critérios avaliados, principalmente a taxa de sobrevivência (75%), a produção relativa, a produção relativa total e o crescimento em altura. As restantes misturas ou não apresentaram diferenças significativas relativamente aos tratamentos puros das respetivas espécies ou apresentaram um efeito depressivo da robínia sobre a espécie principal. O processo de facilitação/complementaridade proporcionado pela espécie acessória é evidente apenas para a cerejeira que beneficia de uma maior quantidade de azoto no solo e uma maior frescura proporcionada pela espécie acessória.

Mixed-species plantations of eucalypts and acacias have the potential to improve stand productivity over that of respective monocultures through the facilitative effect of nitrogen-fixation by acacias, and increased resource capture through above- and belowground stratification. However, growth in mixed-species plantations may not be improved compared to that of monocultures when competitive interactions outweigh the effects of improved nutrient availability and resource capture. Careful selection of sites and species is therefore critical to successfully improving stand productivity using mixed-species plantations. This study set out to examine some of the processes and interactions that occur in mixed-species plantations, and the effect nutrient and water availability can have on the growth of mixtures. ¶ In three out of four mixed-species field trials examined in this study, growth was not increased in mixtures compared to monocultures. However, in the fourth field trial, heights, diameters, stand volume and aboveground biomass were higher in mixtures of E. globulus and A. mearnsii from 3-4 years after planting. ¶ ...

Explores the prominent role of Highland Scots in the exploitation of enslaved Africans and their descendants in the cotton, sugar and coffee plantations of the 18th and 19th centuries. Pays special attention to the new colonies of the southern Caribbean, including Grenada and Guyana, and to Suriname in the years to 1863 Contributes to the debate on reparation by reappraising the idea of Scots complicity in the slave trade Includes a short foreword by Rod Westmaas and Juanita Cox-Westmaas, co-founders of Guyana Speaks, an organisation for the Guyanese diaspora in London Scots were involved in every stage of the slave trade: from captaining slaving ships to auctioning captured Africans in the colonies and hunting down those who escaped from bondage. This book focuses on the Scottish Highlanders who engaged in or benefitted from these crimes against humanity in the Caribbean Islands and Guyana, some reluctantly but many with enthusiasm and without remorse. Their voices are clearly heard in the archives, while in the same sources their victims’ stories are silenced – reduced to numbers and listed as property. David Alston gives voice not only to these Scots but to enslaved Africans and their descendants – to those who reclaimed their freedom, to free women of colour, to the Black Caribs of St Vincent, to house servants, and to children of mixed race who found themselves in the increasingly racist society of Britain in the mid-1800s. As Scots recover and grapple with their past, this vital history lays bare the enormous wealth generated in the Highlands by slavery and emancipation compensation schemes. This legacy, entwined with so many of our contemporary institutions, must be reckoned with.

AbstractThe literature is abound with references to the potential of indigenous and local knowledge (ILK) for sustainable landscape management, but empirical on-the-ground efforts that demonstrate this potential are still lacking. To identify interventions for improving the effectiveness and efficiency of forest restoration, participatory trials were set out in the Indian Himalaya, where per capita degraded land far exceeds per capita cropped/healthy forest land. Treatments were designed based on pooled indigenous and scientific knowledge taking into account farm-forest-livelihood interactions in cultural landscapes. The multipurpose tree-bamboo-medicinal herb mixed restoration plantation reached a state of economic benefit/cost ratio >1 in the eighth year and recovered 30–50% of flowering plant species and carbon stock in intact forest. The communities maintained but did not expand restoration in the absence of policies addressing their genuine needs and aspirations. Transformative change for sustainable restoration would include (1) nesting restoration in participatory, long-term, adaptive and integrated landscape development programmes, (2) formally involving communities in planning, monitoring, bioprospecting, and financial management, (3) assuring long-term funding but limited to the inputs unaffordable for local people, (4) stimulating the inquisitive minds of local people by enriching ILK and cultural heritage, (5) convincing policymakers to provide the scientific rationale behind policy stands, to support the regular interactions of communities with researchers, traders, and industrialists, to commit to genuine payment for ecosystem services in unambiguous terms at multiple spatial (household, village and village cluster) and temporal (short, medium and long-term) scales, and to support long-term participatory action research for development of “landscape restoration models” in varied socio-ecological scenarios.

AbstractA project entitled, “Building village economies through climate farming & forest gardening” (BeChange) was implemented in four municipality areas of the Tanahun and Lamjung districts of Nepal from May 2015. In order to assess changes in the social-ecological system that result from this project targeting abandoned agricultural lands, this case study was conducted using various methods: triad grouping, GPS point surveys, household surveys, focus group discussions (FGDs), field observation and reports. A participatory approach in reforestation on abandoned agricultural land with introduction of carbon credits has become a new livelihood strategy for local communities. It has not only attracted domestic and international tourists, but also helped to conserve biodiversity and local ecology. This activity also united village women and indigenous communities as triad groups for collaborative outcomes. A total of 42,138 seedlings of mixed tree species such as Michelia champaca, Elaeocarpus ganitrus, Bassia butyraceae, Bauhinia purpurea, and Cinnamon tamala were planted by 276 families on abandoned agricultural land between May 2015 and July 2018. However, as of 2020, this range has expanded to include 635 families with plantations of more than 65,000 seedlings. The set-up and maintenance of these forest gardens were financed with advanced payments for the carbon sink services of the planted trees. Farmers who succeeded with tree survival rates above 80% received an additional yearly carbon sink payment. The outcomes of the project show significant improvements in food security and tree biodiversity in the project villages. Of the total sampled households, almost half (45%) were under extreme poverty and had food sufficiency for only 3 months/year before the project. With the project, this percentage dropped to 22%, signals the emergence of seeds for transformative change.

Tropical cloud forests play a fundamental role in the hydrological cycle of mountain watersheds having the largest biodiversity per unit area. In Venezuela, cloud forests are subject to intense deforestation and fragmentation by farming and cattle-ranching causing soil erosion, water cycle alteration, and biodiversity loss. Reforestation projects used exotic species as Pines and Eucalyptus, native species were rarely planted by lacking knowledge on species requirements and management. We report the performance of 25 native cloud forest species differing in shade-tolerance, planted in mixed assemblies on degraded areas. Tree survival and the individual tree variables: total height, root-collar diameter, tree-slenderness, and crown-ratio were evaluated at 1, 2, 4.5 and 7 years-old. Data was analyzed with a repeated measures analysis of variance mixed model considering species shade-tolerance, light intensity at planting and age as explanatory factors. Survival was over 80%. Shade-intolerant species displayed faster height and root-collar diameter growth. Shade-tolerant species had larger crown ratios due to persistence of lower branches; whereas, shade-intolerant showed signs of crown recession at age 7. Slenderness values from age 4.5 were indicative of good trees stability and health across treatments. The positive results have motivated landowners to establish native species plantations in critical areas with our support.

The formation of artificial linear plantations with the participation of pedunculate oak is predetermined by agrotechnical and silvicultural methods of cultivation. Its share among the used other breeds is about 25%. At the age of 33, with the placement of planting places 5.0 x 3.0 m, the pedunculate oak has a high preservation (by 33.9%) in a three-row plantation, in relation to crops from four rows. The protective height in a narrower artificial linear plantation is 10.2 m, which is 1.24 times higher with a width of 20.0 m. In mixed oak-ash crops at the age of 45 years, the best growth and preservation of pedunculate oak is noted in relation to oak plantations pure in composition. For birch-oak crops, the influence of a fast-growing breed is characteristic. At the age of 54, the safety of pedunculate oak is 23.1%, the wind protection height is 19.1 m. Differences in the growth of species are one class of bonitet. In the central rows of pedunculate oak at the age of 30-49 years, the average height has a greater value and a smaller diameter in relation to the indicators of the edging rows (by 7.5-19.9%). A convex transverse profile of the plantation is formed, which is predetermined by the physiological characteristics of the development of the tree species.

Forest reclamation complexes in the Rossoshan district of the Voronezh region are mainly represented with the participation of white acacia, silver birch, green ash, common elm and Tatar maple. The area occupied by them in the agricultural landscape is 2009 hectares. In cultures of hanging birch at the age of 19 years with a change in width from 6.0 m to 15.0 m, there is a decrease in the preservation of species by 8.8% and a decrease in wind protection height by 16.5% with a plant density of 3334 pcs / ha and placement of 3 , 0 x 1.0 m. According to the growth of plantings, they are estimated as Ia class of bonitet. In mixed crops aged 34 years, consisting of fast-growing and accompanying species with a planting width of 16.0 m, the highest height is for drooping birch (20.1 m), the lowest for green ash (14.3 m). The safety of such breeds is 46.8% and 60.6%, respectively. Forest belts, represented by white acacia, drooping birch, Tatar maple at the age of 36 years, have a preservation of species of 38.3-55.2%. The drooping birch has the highest height (22.4 m). In artificial linear plantations, consisting of common elm, drooping birch, Tatar maple and green ash at the age of 38 years, the greatest preservation is observed in the Tatar maple (54.7%), the lowest in green ash (32.7%). The drooping birch has the greatest windproof height (20.6 m) and is estimated in growth according to the Ia class of bonitet. Each breed has certain ecological and biological properties.