Planted Tree Species Research Articles

Medium and large mammals: indicators of buffer zones in reforestation

The activities developed in forest environments such as deforestation, logging, implementation of farming systems and monocultures, together with the advance in soybean production, increase the anthropogenic effects caused by changes to the environment in the so-called Deforestation Arc. The withdrawal of native forests leads directly to losses in biodiversity, however, some measures of natural resource management can be taken to mitigate the deleterious effects, such as the planting of mixed stands. This management is developed through the planting of tree species, native and / or exotic, in a consortium. Strategically, the application of these systems can favor with the maintenance and even with the increase of biodiversity, as these block the perpetuation of edge effects, and often provide high availability of food resources when compared to monoculture systems. In this context, we evaluated by means of photographic traps the presence of said fauna in the altered environments. The fauna present in these environments performs physiological and behavioral activities and consequently maintain the environmental dynamics, through the dispersion of seeds brought from adjacent forest habitats. The present study was carried out in southern Amazonia, in the municipality of Cotriguacu, Mato Grosso, Brazil, in order to verify the use of the environment managed by teak intercropping (Tectona grandis L. f.) With 10 other native species of the region. In this way reforestation areas can contribute to the conservation of forest species, reducing the impact of edge effect over time, providing the mammals and others, and can contribute to the conservation of these species, as they function as relaxation zones, where environmentally friendly animals no longer compete for natural resources in native forest environments, thus complementing their ecological demands.

Effects of Drought on the Phenology, Growth, and Morphological Development of Three Urban Tree Species and Cultivars

Under changing climatic conditions, drought may become a critical constraint for trees in urban areas, particularly at roadsides and highly paved squares. As healthy urban trees have proven to be an important mitigation and adaptation tool for climate change as well as a significant provider of ecosystem services, there is a need for planting species and cultivars capable of coping with the limited water supply. However, data on species’ and cultivars’ response to drought, particularly their water supplying root systems remains rare. To consider the whole plant responses to drought situations, we studied the growth and phenology of three frequently planted tree species and cultivars with a diameter of 5–6 cm during a one-year rainfall exclusion experiment conducted in a nursery field as well as the dry biomass of the compartments branch, stem, and root after excavation. Our results revealed that species’ and cultivars’ performance were linked to their within-plant carbon partitioning. A high tolerance to drought was noted for Acer campestre, with a particularly high ratio of root:shoot ratio, which made it presumably less susceptible to droughts. Tilia cordata ‘Greenspire’ was highly affected by the reduced water availability visible through prematurely leaf senescence, while Carpinus betulus ‘Fastigiata’ suffered from losing a considerable part of its root biomass, which resulted in the lowest root:shoot ratio of all species and cultivars. This study demonstrated the need for investigating the reaction patterns of species and cultivars by considering both the above-and the below-ground plant parts. We recommend that, for future tree plantings at harsh and challenging urban sites, an important selection criterion should be species’ and cultivars’ capability to develop and retain strong and dense root systems even under limited water supply, as that is believed to be an important trait for drought tolerance.

Assessing and modeling total height and diameter increment of ponderosa pine planted in Minnesota, USA

Forest managers are increasingly planting non-native tree species that are adapted to anticipated future conditions such as increased droughts. This work quantified individual tree growth patterns of ponderosa pine (Pinus ponderosa P. & C. Lawson), a western US species, planted outside of its natural range in Minnesota, USA. After 50 years, survival was as high as 69% for some ponderosa pine seed sources, and individuals from the Black Hills, Eastern High Plains, and South and East Montana regions of the western US were some of the tallest and largest diameter trees grown in Minnesota. Predictions of total tree height and diameter increment displayed the lowest bias when equations for ponderosa pine in the western US were used rather than equations for red pine (Pinus resinosa Ait.) in Minnesota, a species that occupies a similar ecological niche. These results indicate that using existing growth and yield equations from a species’ native range may provide a suitable representation of growth and yield patterns if observations from outside the species’ native range are lacking. Historical data from provenance trials such as these can provide a long-term record to quantify the growth potential of non-native species in anticipation of future climate scenarios.

Looking for a home: Exploring the potential of epiphytic lichens to colonize tree plantations in a Macaronesian laurel forest

Mankind has been altering native forests in Macaronesia for at least five centuries. Forestry practices are known to reduce biodiversity due to habitat loss, fragmentation and alteration. To assess the potential of plantations to provide habitat for epiphytic lichens in comparison with native forests, we examined three types of forest in the Canary Islands: laurel forest (native forest) and two monospecific plantations of Pinus radiata and Eucalyptus globulus. Epiphytic lichen diversity was evaluated using a methodology of species richness and lichen diversity values (LDV). Our results demonstrate that the conversion of laurel forests to monoculture plantations of exotic tree species decreases lichen diversity and alters lichen community composition. Our findings hightlight how native epiphytic lichens from the cloud forest cannot survive under the same climatic conditions if the host plant community is changed.

In-stand debarking with the use of modified harvesting heads: a potential solution for key challenges in European forestry

Modern forestry is increasingly confronted with challenges that appear with intensive forest management and the progression of the effects of climate change. The forestry sector is able to react to the changing conditions by adapting management plans, forest structure or planting tree species with a higher stress resistance. However, during stand management activities, silvicultural treatments and harvesting operations can have an impact on the further development of the remaining forest ecosystem. In Germany, the most widely used harvesting system for thinning operations is a single-grip harvester used for felling and processing trees followed by a forwarder for timber extraction from the machine operating trails to roadside. In this research project, debarking rollers and other modifications designed for Eucalyptus harvesting heads were tested on conventional harvesting heads for the first time to assess the possibility of adding debarking to mechanized forest operations under Central European conditions. Seven field tests with varying tree species, diameters and age classes, were established within German state forests in Lower Saxony and in Bavaria. These tests were repeated in both summer and winter seasons to evaluate the influence of associated tree sap flows on debarking quality. Three different harvesting heads were modified to assess the altered mechanical characteristics and setups. To assess debarking ability originating from head modifications, a photo-optical measurement system developed within the scope of the project was used. The results demonstrate that especially for summertime operations, simple modifications to currently used harvesting heads are able to provide an average debarking efficiency up to 90% depending on the modifications. Another key finding is that a negatively affected sap flow, experienced during wintertime operations, resulted in 46% lower debarking efficiency, while spruce bark beetle infestations only resulted in a wider spread of the variation. Additionally, the vertical position of the log within the tree proved to have an influence on debarking efficiency, resulting in 15% lower average debarking for butt logs and 9% for top logs as compared to middle logs. Since a debarking process requires the stem to be fed through the harvesting head on multiple occasions to remove bark, average harvesting productivity might be reduced by approx. 10% compared to productivity measured with conventional harvesting heads. Considering the results and the extent of the modifications, the system proved to be a potential addition to existing harvesting methods facing changing challenges in future forestry.

Effects of restoration on tree communities and carbon storage in rainforest fragments of the Western Ghats, India

AbstractEcological restoration is a leading strategy for reversing biodiversity losses and enhancing terrestrial carbon sequestration in degraded tropical forests. There have been few comprehensive assessments of recovery following restoration in fragmented forest landscapes, and the efficacy of active versus passive (i.e., natural regeneration) restoration remains unclear. We examined 11 indicators of forest structure, tree diversity and composition (adult and sapling), and aboveground carbon storage in 25 pairs of actively restored (AR; 7–15 yr after weed removal and mixed‐native tree species planting) and naturally regenerating (NR) plots within degraded rainforest fragments, and in 17 less‐disturbed benchmark (BM) rainforest plots in the Western Ghats, India. We assessed the effects of active restoration on the 11 indicators and tested the hypothesis that the effects of active restoration increase with isolation from contiguous and relatively intact rainforests. Active restoration significantly increased canopy cover, adult tree and sapling density, adult and sapling species density (overall and late‐successional), compositional similarity to benchmarks, and aboveground carbon storage, which recovered 14–82% toward BM targets relative to NR baselines. By contrast, tree height–diameter ratios and the proportion of native saplings did not recover consistently in actively restored forests. The effects of active restoration on canopy cover, species density (adult), late‐successional species density (adult and sapling), and species composition, but not carbon storage, increased with isolation across the fragmented landscape. Our findings show that active restoration can promote recovery of forest structure, composition, and carbon storage within 7–15 yr of restoration in degraded tropical rainforest fragments, although the benefits of active over passive restoration across fragmented landscapes would depend on indicator type and may increase with site isolation. These findings on early stages of recovery suggest that active restoration in ubiquitous fragmented landscapes of the tropics could complement passive restoration of degraded forests in less fragmented landscapes, and protection of intact forests, as a key strategy for conserving biodiversity and mitigating climate change.

Do horticultural tree plant species depend on mycorrhizal inoculation under marginal soil conditions?

Do horticultural tree plant species depend on mycorrhizal inoculation under marginal soil conditions?

Characteristic and Diversity Vegetation of Bukit Tiga Puluh National Park as Dietary Sources for Reintroduced Sumatran Orang Utan (Pongo abelii Lesson)

<p>The population of Sumatran orang utan in natural habitat has been declined and threatened with extinction. The orang utanreintroduction program is expected to increase breeding and population in nature. This study aimed to analyze the important value index of vegetation as well as the diversity and abundance species of Bukit Tiga Puluh National Park (BTNP) as dietary sources for reintroduced Sumatran orang utan. The research was conducted during two years from 2015 to 2016. The data collection for flora characteristics is done through the vegetation analysis with strip transects method. Plots were selected by stratification method based on the resort management and the land cover, like primary and secondary forests. Total flora species on a plot of 2.8<br />ha were identified about 301 species. The highest variation found in Suo-Suo Resort (139 species) and the lowest in Talang Lakat Resort (82 species). The dominant species have been found were Eugenia grandiflora O. Berg, Macaranga lowii King ex Hook.f., Shore iliginosa Foxw., and Tarrietia rubiginosa Kostern. Vegetation chararacteristic to be identified were tree density of 350-552.5 individuals/ha, species diversity index of 2.86-4.19, and abundance index of 32.1087.35. It also identified that vegetation characteristic among resort and land cover were different (p <0.05). Moreover, there were about 110 species of tree plants including of 31 families that found as dietary sources for orang utan and leaves became the highest plant parts which consumed by orang utans (41.8%) compared to other parts. Based on area size, ecosystem types as well as vegetation composition and variation, BTNP may support the increasing population of orang utans. However, there needs to be considered that other<br />aspects such as high human activity within the conservation area, particularly by Talang Mamak tribe communities, may cause unsuccessful achievement on reintroduction program of orang utan.</p>

Use of Time-of-Flight Ultrasound to Measure Wave Speed in Poplar Seedlings

In this study, 145 poplar (Populus × euramericana cv.’74/76’) seedlings, a common plantation tree species in China, were selected and their ultrasonic velocities were measured at four timepoints during the first growth year. After that, 60 poplar seedlings were randomly selected and cut down to determine their acoustic velocity, using the acoustic resonance method. The effects of influencing factors such as wood green density, microfibril angle, growth days, and root-collar diameter on acoustic speed in seedlings and the relationship between ultrasonic speed and acoustic resonance speed were investigated and analyzed in this work. The number of specimens used for investigating growth days and root-collar diameter was 145 in both cases, while 60 and two specimens were used for investigating wood density and the microfibril angle, respectively. The results of this study showed that the ultrasonic speed of poplar seedlings significantly and linearly increased with growth days, within 209 growing days. The ultrasonic velocity of poplar seedlings has a high and positive correlation with growth days, and the correlation was 0.99. However, no significant relationship was found between the ultrasonic velocity and root-collar diameter of poplar seedlings. Furthermore, a low and negative relationship was found between wood density and ultrasonic speed (R2 = 0.26). However, ultrasonic velocity significantly decreased with increasing microfibril angle (MFA) in two seedlings, and thus MFA may have an impact on ultrasonic speed in poplar seedlings. In addition, ultrasonic velocity was found to have a strong correlation with acoustic resonance velocity (R2 = 0.81) and a good correlation, R2 = 0.75, was also found between the dynamic moduli of elasticity from ultrasonic and acoustic resonance tests. The results of this study indicate that the ultrasonic technique can possibly be used to measure the ultrasound speed of young seedlings, and thus early screen seedlings for their stiffness properties in the future.

Effects of arbuscular mycorrhizal fungi on inoculated seedling growth and rhizosphere soil aggregates

Arbuscular mycorrhizal fungi (AMF) inoculation have been shown to enhance host plant growth and rhizosphere soil aggregates largely due to the combined effect of extraradical hyphae and glomalin-related soil proteins but their effects on rocky desertified soils remain unknown. Extensive karst area of southwest China has undergone rocky desertification because of soil erosion and vegetation degradation. Karst soils in this area are mainly composed of silty clay loam developed from carbonate rock erosion under subtropical humid monsoon climate. We tested the hypothesis that AMF colonization of tree seedlings would improve water stable aggregates of degraded karst soil and enhance seedling growth. Seedlings of two tree species, Toona sinensis and Delavaya toxocarpa suitable for afforestation in karst area, were inoculated separately with three AMF, Funneliformis mosseae, Glomus versiforme and Rhizophagus intraradices in pots containing rocky desertified soil. Non-inoculated seedlings were used as control. After 12 months we found that the percentage of water stable aggregates (diameter >0.25 mm; WSA>0.25) in the rhizosphere soil of the inoculated seedlings was increased by 15.6–20.5% compared to control. AMF colonization significantly increased the quantity of aggregates with diameter > 2 mm compared to control but soil aggregates of size class 0.25 – 0.5 mm decreased significantly in inoculated seedlings, regardless of tree species. Shoot biomass of inoculated T. sinensis and D. toxocarpa seedling was increased by 15.7–21.2% and 8.5–20.4%, respectively compared to non-inoculated seedlings. In contrast, AMF inoculation minimally influenced the root biomass of the two tree species. The easily extractable glomalin (EEG) content and mean weight diameter (MWD) of rhizospheric soil of the inoculated seedlings increased by 28.9–75.1% and 31.7–48.1%, respectively compared to control. The AMF colonization was highly correlated with WSA>0.25, EEG and MWD. Overall results support our hypothesis that AMF colonization enhance the quantity of rhizospheric soil aggregates and improve the growth of host seedlings. We conclude that planting tree species inoculated with AMF has a potential for restoration of degraded karst ecosystem. In future research other locally adapted tree and shrub species should be tested following AMF inoculation to prepare a wider planting stocks to be used in restoration of degraded karsts.

Исследования по засухоустойчивости видов рода CELTIS L. для лесомелиоративных насаждений

Ограничивающими факторами функционирования лесомелиоративных насаждений в Нижнем Поволжье являются дефицит влаги в период вегетации, высокие и низкие температуры, также лимитируют ареал устойчивой культуры растений. Поиск новых древесных видов для лесомелиоративных насаждений Нижнего Поволжья остается весьма актуальным, особенно по отношению к засушливым условиям (42C, минимальная влажность воздуха в пределах 1625, снижение влаги в 2 м слое почвы до 150 мм). Из семейства каркасовых (Celtidaceae Link) представляет интерес родовой комплекс каркас (Celtis L.). Цель исследований выявление засухоустойчивых видов рода Celtis L. по комплексу экологофизиологических параметров для применения в лесомелиоративных насаждениях в Нижнем Поволжье. Объектами исследований являлись 7 видов родового комплекса Celtis L. (C. bungeana Blume., C. occidentalis L., C. caucasica Willd., C. pumila Pursh, C. reticulata Torr., C. crassifolia Lam., C. australis L.), различного географического происхождения, которые произрастают в коллекциях ФНЦ агроэкологии РАН (Волгоград, Камышин). Выявлено, что низкий водный дефицит (до 20 ) наблюдается у видов Celtis L. (C. occidentalis L., C. reticulata Torr., C. crassifolia Lam., C. australis L. и C. bungeana Blume.). Изученные виды Celtis L. разделены на первую (относительный выход электролитов 1,411,69) и вторую (2,082,41) группы по степени засухоустойчивости. У видов Celtis L. с возрастом происходит адаптация на морфофизиологическом уровне, которая способствует расширению пределов толерантности видов к неблагоприятным условиям среды. Для лесомелиоративных насаждений на лесопригодных почвах региона (все подтипы каштановых почв) рекомендуются Celtis occidentalis, C. crassifolia, C. reticulata, C. australis, C. bungeana (засухоустойчивые виды первой группы). Наши исследования по засухоустойчивости видов рода Celtis L. указывают на перспективность при подборе растений для лесомелиоративных насаждений использование следующих критериев по экспериментам: оводненность, водоудерживающая способность, водный дефицит, относительный выход электролитов. The limiting factors of the functioning of forest melioration plantations in the Lower Volga region are moisture deficiency during the growing season, high and low temperatures, and also limit the area of sustainable plant culture. The search for new tree species for forest melioration plantations in the Lower Volga region remains highly relevant, especially in relation to dry conditions ( 42 C, minimum air humidity within 1625, reduction of moisture in 2 mm soil layer to 150 mm). From the family of skeletons (Celtidaceae Link), the generic complex skeleton (Celtis L.) is of interest. The purpose of the research is to identify droughtresistant species of the genus Celtis L. using a set of ecological and physiological parameters for use in forest melioration plantings in the Lower Volga region. The objects of research were 7 species of the clan complex Celtis L. (C. bungeana Blume., C. occidentalis L., C. caucasica Willd., C. pumila Pursh, C. reticulata Torr., C. crassifolia Lam., C. australis L .), of various geographical origin, which grow in the collections of the Federal Science Center of Agroecology RAS (Volgograd, Kamyshin). It was revealed that a low water deficit (up to 20) is observed in the species Celtis L. (C. occidentalis L., C. reticulata Torr., C. crassifolia Lam., C. australis L. and C. bungeana Blume.). The studied species of Celtis L. were divided into the first (relative yield of electrolytes 1.411.69) and the second (2.082.41) groups according to the degree of drought tolerance. In Celtis L. species, they adapt with age at the morphophysiological level, which contributes to the expansion of the tolerance limits of the species to unfavorable environmental conditions. For forest reclamation plantations on forest soils of the region (all subtypes of chestnut soils) are recommended Celtis occidentalis, C. crassifolia, C. reticulata, C. australis, C. bungeana (droughtresistant species of the first group). Our studies on the drought tolerance of species of the genus Celtis L. indicate the prospects for selecting plants for forest melioration plantings using the following experimental criteria: water content, water holding capacity, water deficit, relative electrolyte yield.

TREE SPECIES DIVERSITY, STRUCTURAL CHARACTERISTICS AND CARBON STOCK IN A ONE-HECTARE PLOT OF THE PROTECTION FOREST AREA IN WEST LAMPUNG REGENCY, INDONESIA

HERIYANTO, N. M., SAMSOEDIN, I. & KARTAWINATA, K. 2018. Tree species diversity, structural characteristics and carbon stock in a one-hectare plot of the protection forest area in West Lampung Regency, Indonesia. Reinwardtia 18(1): 1‒18. — A study of species composition, structure and carbon stock in the lower montane forest in the Register 45B of the protection forest area in the Tri Budi Syukur District, Kebun Tebu Village, West Lampung Regency, Lampung Province was conducted in September 2016. The objective of the study was to undertake quantified measurements of floristic composition and structure of and carbon storage in the lower montane forest at 965 m asl in the protection forest area. A one hectare plot (100 m × 100 m) was established randomly. The plot was further divided into 25 subplots of 20 m × 20 m each to record trees. Quadrats of 5 m × 5 m for saplings and subquadrats of 2 m × 2 m for seedlings were nested in the tree subplots. We recorded 247 trees with diameter at breast height ≥ 10 cm representing 25 species and 19 families, with a total basal area of 59.14 m2. Overall including seedlings and saplings we recorded 31 species. The species richness was very low due to disturbances, and was the lowest compared to that of other forests in Sumatra, Kalimantan and Java. The dominant species in terms of importance values (IV) were Litsea cf. fulva (IV=77.02), Lithocarpus reinwardtii (IV=45.21) and Altingia excelsa (IV=26.95). Dominant species in seedling and sapling stages were Polyalthia lateriflora (IV=27.54) and Memecylon multiflorum (IV=41.58). Biomass and carbon stock of trees with DBH ≥ 10 cm was 50.87 ton/ha and 25.43 ton C/ha, respectively. Regeneration was poor. Structurally and floristically the forest was a developing disturbed forest and the composition will remain unchanged in many years to come. The successions leading to terminal communities similar to the original conditions would be very slow and should be assisted and enhanced by applying ecological restoration through planting tree species native to the site.

Orthotropic Tension Behavior of Two Typical Chinese Plantation Woods at Wide Relative Humidity Range

Research Highlights: Orthotropic tension behaviors of poplar and Chinese fir were investigated at a wide relative humidity (RH) range. Background and Objectives: Poplar and Chinese fir are typical plantation tree species in China. Mechanical properties of plantation-grown wood varies from naturally-grown one. To utilize poplar and Chinese fir woods efficiently, fully understanding their moisture content (MC) and orthotropic dependency on tension abilities is necessary. Materials and Methods: Plantation poplar and Chinese fir wood specimens were prepared and conditioned in series RH levels (0–100%). Tensile modulus (E) and strength (σ) were tested in longitudinal (L), radial (R), and tangential (T) directions. Results: The E and σ results in transverse directions confirmed the general influence of the MC that decreased with increasing MC. However, both E and σ in L direction showed a trend that increased at first, and then decreased when MC increased. The local maximums of stiffness and strength may be associated with straightened non-crystalline cellulose, induced by the penetration of water into the wood cell wall. Using the visualization method for compliance, the tension abilities of poplar and Chinese fir exhibited clear moisture and orthotropic dependency. Conclusion: Both poplar and Chinese fir showed a significantly higher degree of anisotropy in the L, R, and T directions. The results in this study provided first-hand data for wooden construction and wood drying.

Birds associated with different tree species and structures in oil palm agroforestry landscapes in Malaysia

ABSTRACTThe expansion of oil palm (Elaeis guineensis) cultivation has been recognised as a major threat to tropical biodiversity. Smallholdings, however, unlike large-scale conventional monoculture oil palm plantations, often practice polyculture which may resemble an agroforestry system. These private holdings provide more heterogeneous vegetation which may support greater a greater diversity of birds. This study compared species richness and abundance of birds detected perching in oil palm (both dead and living trees) and seven other planted crop species within oil palm smallholdings. Using transect line surveys, we recorded a total of 816 birds of 39 species from 20 families. Our results indicate that bird species richness and abundance differed significantly between oil palm and the other planted tree species. Non-oil palm trees cumulatively increased bird species richness and abundance. Although birds overall perched more frequently on living oil palm trees (probably reflecting relative abundance), other species including breadfruit, mango, papaya, banana, and coconut, as well as dead trees, were also used. By measuring effect size, we also found that both bird species richness and abundance rely on tree structure and type of tree species. These findings tentatively suggest that providing a larger diversity of tree species within intensively managed oil palm plantations may support a wider variety of local bird species compared to monocultures.

Modeling the height-diameter relationship of planted Pinus kesiya in Zambia

Plantations of non-native tree species cover over 50,000 ha in Zambia of which Pinus kesiya accounts for 36% of the main tree species. In order to quantify the growing stock of P. kesiya, updated and reliable height-diameter (h-d) models are required. Therefore, the aim of this study was to develop appropriate h-d models for P. kesiya that are consistent with current forest management practices in the country. Using 7691 measured pairs of diameter and height of P. kesiya from four different forest sites, the following questions were investigated; (i) do frequently used h-d models accurately estimate height of P. kesiya in Zambia?; and (ii) what h-d models account for site and rotation in the country? Predicted h from the frequently used h-d models (Näslund, Modified Logistic and Hossfeld) was significantly lower than the measured h (p ≤ 0.001). This suggests that frequently used h-d models for pine significantly underestimates tree height of P. kesiya in Zambia. The deviations associated with these models varied but generally increased with tree diameter. In this regard, country level h-d model developed using the Weibull function, and tested in this study proved to be more accurate than the frequently used models in predicting tree height of P. kesiya in Zambia. Furthermore, site and rotation were found to influence the overall accuracy and reliability of the country level model (p ≤ 0.001) suggesting the need to refine this model in order to account for site and/or rotation effect. Therefore, the h-d models that are specific to site and in some instances to rotation were derived and increased the accuracy and precision in estimating tree height of P. kesiya in the country. These locally developed h-d models are recommended for future forest plantation inventories, management planning and as a basis for modeling h-d relationships for other Pinus species in the country.

Does conversion from natural forest to plantation affect fungal and bacterial biodiversity, community structure, and co-occurrence networks in the organic horizon and mineral soil?

Tree species influence the chemical properties of the organic horizon and mineral soil. Microbial communities, including fungi and bacteria, which are the main drivers of nutrient cycles in forest soils, may be affected by tree species via litter chemical properties and root exudation. Therefore, conversion from natural forest to plantation could affect the microbial communities. Here, we aimed to reveal the effects of conversion from natural forest to coniferous plantation on soil microbial community structure, biodiversity, and co-occurrence networks, as well as soil chemical properties. For this purpose, we investigated chemical and microbial properties of the organic horizon and mineral topsoil (0–10 cm depth) in three forest types (a natural forest dominated by broad-leaved deciduous trees, and two types of plantations). Forest type had significant effects on chemical properties, including the C/N ratio, pH, and dissolved inorganic N of the organic horizon, while it had no significant effect on the chemical properties of topsoil, except for microbial biomass N and C. Microbial community structures in both the organic horizon and topsoil differed significantly among forest types and with changes in soil properties such as pH and C/N ratio. Microbial diversity indices did not significantly differ among forest types in either layer, while the microbial co-occurrence networks in the mineral soil of the natural forest were more complex and robust than the networks of plantations. Therefore, our results showed that conversion from natural forest to coniferous plantation could affect soil chemical properties and microbial community structure in the organic horizon, and the microbial co-occurrence network in the mineral topsoil; these impacts may vary according to the planted tree species.

Carbon payments for extended rotations in forest plantations: Conflicting insights from a theoretical model

This study adapts the Faustmann model (1849) to include the effects of carbon-based payments for environmental services on the optimal rotation length of forest plantations. We assume payments occur at the end of the harvesting cycle and are based on the additional average carbon stock over the rotation length relative to an optimal management scenario without carbon incentives. We present numerical applications of our model based on the four most planted tree species in the world: Eucalyptus sp., Acacia sp., Pinus sp. and Tectona sp. Simulations were performed to quantify the impact of different payment levels (USD Mg CO2−1) on optimal rotation lengths and carbon stocks. We find diminishing sequestration returns to increasing carbon payments. Overall, our results suggest that targeting plantations with longer rotations, associated with slow-growing species, is a more cost-effective strategy to retain additional forest carbon stored (USD Mg CO2−1). However, such a strategy results in lower proportional increases in carbon stocks (Mg CO2 ha−1) compared to faster-growing species, which benefit the most from the carbon incentives. As a result, increasing payments for additional carbon stored could change the choice of which tree species to produce and ironically promote plantations with lower total carbon stocks.

Effects of Initial Soil Properties on Three-Year Performance of Six Tree Species in Tropical Dry Forest Restoration Plantings

Deforestation of tropical dry forest reduces soil fertility, with negative effects on future restoration intervention. To evaluate the effect of initial soil properties on three-year performance of six tree species in restoration settings, we measured C, N, and P contents in topsoils of 48 plots under minimal (exclusions of livestock grazing) and maximal (plantings of six native species) restoration intervention during two years in tropical dry forest in central Mexico. Survival and height and diameter relative growth rates were evaluated by species and by growth rank (three fast- and three slow-growing species). After two years, organic C and the C:N ratio increased early during natural succession; these increases might be related to high density of N2-fixing recruits at both intervention levels. Changes in N availability for plants (i.e., NO3− and NH4+ contents) occurred after cattle exclusion. After 40 months, the fast-growing legume Leucaena esculenta (DC.) Benth. had the highest survival (65.55%) and relative growth rate in both height (3.16%) and diameter (5.67%). Fast-growing species had higher survival and diameter growth rates than slow-growing species. Higher diameter growth rates for fast-growing species may be associated with a higher ability to forage for soil resources, whereas similar height growth rates for slow and fast-growing species suggested low competition for light due to slow natural succession at the site. Planted seedlings had higher survival possibly due to initial high NO3− content in the soil. Also, fast-growing species seem to benefit from initially higher pH in the soil. Both soil properties (i.e., pH and NO3−) may be augmented to favor the performance of fast-growing species in restoration plantings and to further accelerate soil recovery in tropical dry forests.

A spatially-explicit empirical model for assessing conservation values of conifer plantations

Plantations are expanding globally and dominate landscapes in many parts of the world. Biodiversity conservation within plantations is becoming an important issue and developing indicators of conservation values is valuable. Although plantations support less biodiversity than natural forests, older plantations can provide habitat for some native trees and associated biota. The amount (basal area) of native trees can be a simple indicator of conservation value of plantations. Various factors are likely to affect rates of increase in native trees in plantations with stand age. We developed an empirical model to predict the amount of broad-leaved trees as an indicator of conservation value of conifer plantations. We quantified relationships between rates of increase in the amount of broad-leaved trees and plantation tree species, density of planted trees, climate, topography and landscape cover. We used a hierarchical modeling framework based on extensive snapshot plot data (n = 3265 plots) from the national forest inventory in Japan. Our results showed that plantation tree species had the largest effect on the rate of increase in broad-leaved trees. Japanese cedar Cryptomeria japonica and hinoki cypress Chamaecyparis obtuse, which are two primary plantation species in Japan (both from the cypress family), had low rates of increase. In plantations of other species (red pine, larch, fir and spruce from the pine family), broad-leaved trees started to increase in amount after 20 years. We found that 50-year-old plantations of the pine family supported 10–20% of the amount of broad-leaved trees typically found in old-growth natural forests. Planted tree density also had important, but nonlinear relationships with the rate of increase in broad-leaved trees. Stands with fewer planted trees had higher rates of increase in broad-leaved trees. Rates of increase also were associated with snow depth, temperature, slope angle and the amount of natural forest in the surroundings. Our results suggest that management practices related to stand age, selection of plantation species and the density of planted trees can contribute to the conservation value of plantations. As our model is based on broadly available covariates and accommodates stand age, it may be applicable to other regions under different management regimes.

Survival, growth, aboveground biomass, and carbon sequestration of mono and mixed native tree species plantations on the Coromandel Coast of India

ABSTRACT In India, reforestation programs with native indigenous tree species are a recent activity. Information on experiences comparing mono- and mixed-species plantations is limited. This study aims to estimate growth, aboveground biomass, and carbon sequestration between the mixed-species plantation and mono-species plantation. The growth, survival, height, aboveground biomass, and carbon sequestration of 82 native mixed species plantations were compared with Casuarina equisetifolia an exotic species planted in this region after over a decade (2006–2016). In the mixed species plantation, 7 species showed 100% survival rate and 19 species were not survived after over a decade intervals. While in the mono plantation, C. equisetifolia showed 92% of the survival rate. The growth rate of mixed species when compared to mono plantation, it showed highly significant differences (P < 0:05) values. Simple linear regression between annual girth increment and height produced very strong positive relations (R 2 0.759). The aboveground biomass estimated for the mixed native plantation was 8.007 tonnes and the mono plantation Casuarina had 5.585 tonnes. The total carbon stock estimated for the tree plantation in the two plots (both mixed native and mono) was 7.492 tonnes. A positive correlation was observed between the carbon stock and density of the top 10 species which contributed predominantly to the total carbon stock (rs = 0.773, p < 0.05). Plantation of C. equisetifolia seems to be well adapted and had more carbon stocking potential. On the other hand, mixed plantation with indigenous species would contribute more to sustainable management and they provide great shelters for many faunal communities and provide a greater range of ecological goods and ecosystem services than the mono plantations.