Growth assessment of upper hill dipterocarp (Shorea platyclados) at the various slope in a rehabilitated landscape

Rehabilitation aims to improve landscape function while increasing its resilience to climate change. Gunung Dahu research forest is a rehabilitated hilly landscape that is planted with more than 25 dipterocarp species, including an upper hill dipterocarp tree of Shorea platyclados at various site conditions. This study aimed to assess the growth performance of S. platyclados at five sloping levels class of 0-8%, 8-15%, 15-25%, 25-45%, and >45%. Observed growth attributes were stem diameter, total height, basal area, Mean Annual Increment (MAI), and Leaf Area Index (LAI), and diameter. The results showed that sloping levels significantly affect the growth performance of the planted trees. The highest slope level (>45%) supported the highest average stem diameter and tree height (41.48 cm and 20.86 m). The sloping level of >45%, 25-45%, 15-25%, 8-15%, and 0-8% yield different value of average diameter which were 41.48 cm, 35.86 cm, 36.54 cm, 34.61 cm, and 31.23, while the average height were 20, 86m, 19.78 m, 16.72 m, 18.84 m, 18.61 m respectively. Thus, the upper hill dipterocarp of S. platyclados is a prospective native tree species for rehabilitating hilly upland landscapes.

The growth performance of dipterocarps species and understorey diversity in the Gunung Dahu Research Forest, Leuwiliang, Bogor

Dipterocarps species is the main species composes Gunung Dahu research forest. Habitat suitability and growth performance of a species are some factors considered in the species selection for forest establishment. The understorey in a forest community serves to protect soil from erosion. This research aimed is to analyze the growth performance of various Dipterocarpaceae species and study understorey diversity in the research area. The measurement was conducted in four species trial plots contain ten Dipterocarps species consist of five individuals per species per plot or 200 individuals in total. The growth performance of Dipterocarp species was analyzed using the current annual increment (CAI) and mean annual increment (MAI) methods. The understorey diversity was analyzed using the Shannon-Wiener Index. The result showed that Shorea johorensis obtained the highest CAI, 0.95 cm year−1, and Shorea platyclados got the highest MAI, 1.78 cm/year. S. platyclados and S. leprosula were projected to reach <40 cm in diameter after they got 25 years. The Gunung Dahu research forest’s understorey was classified as moderate (1.68 - 2.33). The dominant understorey species, namely Oldenlandia auricularia, Neprolephis biserrate, Ottochloa nodosa, and Gleichenia linearis. This study concluded that the growth performance of Dipterocarps species in the study area varied, and the understorey condition was classified as moderate, where its diversity has a positive correlation with the crown openness.

Effect of soil type on mean annual increment, wood anatomy and properties of 33-year-old Corymbia citriodora (Hook.), K. D. Hill, & L. A. S. Johnson

This study aimed to determine the effects of physical, chemical and water-holding capacity of Quartzarenic Neosol, Red Latosol and Red Nitosol on tree growth, physicomechanical properties and anatomical features of wood from 33-year-old C. citriodora plantations. More clayey soils with higher water availability, such as Red Latosol and Red Nitosol, increased the mean annual increment and heartwood percentage. In more sandy soils, such as Quartzarenic Neosol, density increased, but the size and diameter of fibers and vessels decreased, and both fiber cell wall thickness and frequency of vessels and rays increased. Wood shrinkage and mechanical properties did not differ between soils. We observed a gradual increase in the anatomical, physical and mechanical characteristics in the pith-bark direction. The uniformity index showed that Quartzarenic Neosol and Red Latosol soils produced more homogeneous woods. We concluded that soil texture and water availability influenced tree growth, anatomical properties and wood density.

Bioenergy yield of Eucalyptus urophylla clones and its relationship with the mean annual increment of wood volume

This study aimed to evaluate the energy yield and wood characteristics of Eucalyptus urophylla clones with different mean annual increment of wood volume (MAI). The clones presented MAIs of 39.2, 54.1 and 70.0 m3 ha-1 yr-1 in the field experiment at six years after planting when the trees were cut down to evaluate the wood basic density and higher heating values. The energy density, dry mass and energy yield were estimated. The MAI of E. urophylla clones influenced the wood basic density, dry mass, and energy yield, but did not influence the higher heating value and energy density. Clone 3 had the highest MAI, and also had higher energy yield and dry mass, but lower wood basic density. The difference between the most and the least productive clones was 242,648 MJ ha-1 yr-1. The results reinforce the importance of evaluating the wood quantity production (MAI) to select Eucalyptus clones for energy purposes.

Growth performance of Santalum album its income potentiality: A study from Pyuthan District, Nepal

The Santalum album is becoming a popular income generating tree species in Nepal but its growth performance has not been assessed so far yet. Thus, this study was objectively conducted to assess mean annual increment, income from Santalum album and value chain analysis. The Private plantation of Pyuthan district was selected for the study site. The diameter and height of 450 plants were measured and their age was recorded. Total fifteen key informant interviews, forty five farmers’ interviews and one focused group discussion were conducted to collect primary data. The collected data were analyzed using descriptive and inferential statistics .Mean annual increment, price of Santalum album and contribution of Santalum album in total income were analyzed. The result showed that the highest mean annual diameter increment was 51.94 cm and lowest mean annual increment was 28.25cm, the highest mean height increment was 6.39 m and the lowest mean annual height increment was4.47m and the highest mean volume increment was 0.678 m3but the lowest mean annual volume increment was 0.134 m3. The estimated maximum range of annual income from Santalum album was US$ 221-530 which was 10-15% contribution in farmers annual income while minimum range of this was US$ 194-265 and it contributes<10%.The difference of the price of Santalum album between the farmers and users in Kathmandu was2200 times more.

Comparing long-term projected outcomes of adaptive silvicultural approaches aimed at climate change in red pine forests of northern Minnesota, USA

The Adaptive Silviculture for Climate Change (ASCC) project was developed to test ecosystem-specific adaptation approaches. The first ASCC trial was installed on the Cutfoot Experimental Forest (CEF) in northern Minnesota, USA in 2014. Three adaptation treatments (resistance, resilience, and transition) along with a no action control, were tested and compared using Forest Vegetation Simulator to determine their relative success. We compared mean annual increment (MAI) and mortality and determined how well each treatment achieved its species composition and stand structure targets. MAI was highest in the no action (3.77 ± 0.43 m3 ha-1 yr-1) and lowest in the transition (1.72 ± 0.16 m3 ha-1). However, MAI for the transition treatment continually increased over time, which extended culmination age. The no action had the highest mortality with 38.76 (± 1.32) TPH per 10-year timestep, while the resistance and transition treatments had the lowest levels, at 9.36 (± 0.49) and 4.19 (± 0.35) TPH, respectively. Our findings highlight the relative success of the transition, which had lower mortality, greater structural diversity, and a future-adapted species composition. Results from this study provide important context for adaptive silviculture aimed at climate change and offers an example of potential outcomes of these forest adaptation options.

Tree dimension and environmental correlates of heartwood content in Siamese rosewood (Dalbergia cochinchinensis)

Meunpong P, Penboon C, Kuasakun N, Wachrinrat C. 2021. Tree dimension and environmental correlates of heartwood content in Siamese rosewood (Dalbergia cochinchinensis). Biodiversitas 22: 3297-3303. Siamese rosewood (Dalbergia cochinchinensis) is considered amongst the prime timber varieties in high demand with the wood fetching high prices in the international timber market. Therefore, illegal logging and smuggling of Siamese rosewood from natural forests poses a severe problem in Thailand. Heartwood and its content is the most valuable part of Siamese rosewood, which in practice, cannot be measured directly in living trees. Hence, we investigated the relationship between the heartwood content of Siamese rosewood, and tree dimension and environmental characteristics across eleven plantations throughout Thailand construct a model for predicting the heartwood content using specific environmental variables. The results indicate that there were differences in the mean annual increment of all measurement parameters (d0, d30, dbh, and total height of a tree) across eleven plantations studied. However, we did not find any statistically significant differences between the increments in heartwood diameter. Furthermore, we found that suitable location for Siamese rosewood plantation could result in doubling of growth rate. We report that dbh was the most relevant variable and could be used as a predictor for heartwood content. In terms of environmental variables, soil properties at top layer that affect the heartwood content were particle density, organic matter, and silt particles. Using the resulted equation formulated in this study may be useful when planning areas for suitable plantations of Siamese rosewood in Thailand.

Dendrochronological study of Cedrus deodar Grown at Kumrat valley Dir Upper KPK, Pakistan: Evaluation of Tree Age and Increment Based on Increment Core

The present research was conducted for tree-rings study in a mixed stand of Himalayan Species Credur deodar in Kumrat valley Dir Upper KPK, Pakistan. Tree-rings analysis was related to the counting of tree ring. Random sampling method was used, and 70 sample trees were selected, tree heights and diameters were measured, and increment cores were collected from each sample-tree diameter at the height at breast point to be analyzed and studied in the laboratory. The objectives of the study were to determine the exact age of tree and to evaluate total and mean annual increment in the basal area and tree volume based on the increment cores. Regression models revealed the impacts of tree age on the basal area and tree-volume increment. Results showed the minimum basal-area increment was 0.0028 m2 at the age of 10 years, the maximum basal-area increment was 2.658 m2 at the age of 60 years, with mean was 0.95±0.677 m2 at the age of 36 years and R2 was 0.9593. The maximum tree-volume increment was 1.42 m3 at the age of 60 years, the minimum tree-volume increment was 0.010 m3 at the age of 10 years, with mean was 1.35±0.96 m3 at the age of 36 years and R2 was 0.9167. The minimum mean annual-basal area increment was 0.0027 m2, the maximum mean annual-basal area increment was 0.048 m2, and the average increment was 0.022±0.010 m2. The maximum mean-annual increment in tree volume was 0.068 m3 at the age of 60 years, the minimum mean-annual increment was 0.0039 m3 at the age of 10 years, with mean was 0.032±0.014 m3 at the age of 36 years and R2 was 0.8903. Results showed a strong positive relationship of tree age with area and volume increment. Keywords: Basal area, increment, tree age, volume

What Can Native Trees Provide in Revegetating Tropical Degraded Land? An Experience of Man-Made Dipterocarp Forest in Indonesia

The benefits of revegetation provided by the successful growth of planted vegetations. This paper described a successful initiative on the revegetation of tropical degraded land using native trees. More than 250 hectares of intact landscape in Gunung Dahu, West Java—Indonesia have been successfully revegetated using 32 Dipterocarp species. The success of this 20-years-old revegetated landscape was revealed by timber volume, natural regeneration, soil characteristics, ectomycorrhiza occurrence, and ecotourism potential. The results showed that the average diameter and height were varied from 12–43 cm and 10–23 m; diameter mean annual increment were at 0.6–2.1 cm year−1; standing stock per hectares were at 10–220.84 m3 ha−1. The variations might be caused by different planted species, spacing distance, and planting technique. The natural regeneration success was observed by the offspring’s occurrence from six Shorea species and supported by mycorrhiza fruiting bodies predominantly by the genus Rusula. Planted trees also improved the availability of organic materials to the soils, as described by the good total soil porosity (51.06–52.32%) and infiltration rate (120–15,533 mm hour−1) at the site. The landscape also provided springs with continuous water supply and allowed tourists to experience the serenity of the tropical forest. Hence, revegetation using a native tree is prospective and proven to deliver a wider benefit in the ecological, economic, and social aspect.