Teak Plantations Research Articles

Optimizing thinnings for timber production and carbon sequestration in planted teak (Tectona grandis L.f.) stands

Aim of study: We developed an optimization model for determining thinning schedules in planted teak (Tectona grandis L.f.) stands that maximize the financial output in terms of soil expectation value (SEV) and net present value (NPV) considering a) the simultaneous optimization of timber production and carbon (C) sequestration and b) only for C sequestration.Area of study: Planted teak forests in the western alluvial plains of Venezuela.Material and methods: We integrated a stand growth and yield model with a constrained optimization model based on genetic algorithms (GA) for determining optimal thinning schedules (number, age, and removal intensity) that maximize SEV when simultaneously managing for timber production and C sequestration. The data came from permanent plots established in planted teak stands with remeasurements from 2 to 32 yr.-old. Plots differ in site quality, initial spacing, and thinning schedules. We obtained optimal thinning schedules for several scenarios combining site quality, initial spacing, interest rates, harvest and transport costs, as well as timber and C prices. The stand growth and yield model estimates timber products and C flows (storage and emissions) until most stored C is reemitted to the atmosphere.Main results: When considering simultaneously both, timber production and C sequestration, the scenario with the maximum SEV consisted of initial stand densities = 1,111 trees ha-1, site quality (SQ) I, harvest age 20 years, and four thinnings (ages 6, 10, 14, 17 with removal intensities 26 %, 28 %, 39 %, and 25 % of stand basal area respectively). For maximizing C sequestration only, the best schedule consisted of 1,600 trees ha-1, SQ I, harvest age 25 years, with no-thinning. A sensitivity analysis showed that optimal schedules and SEV were highly sensitive to changes in interest rates, growth rates, and timber prices.Research highlights:The management schedules favoring merchantable timber production are not the same that favor C sequestration.For planted teak, the objectives of maximizing timber production and carbon sequestration are in conflict because the thinning schedules that maximize financial gains from C sequestration reduce economic gains from timber and vice versa.With actual timber teak and market C prices, optimal NPVW is much larger than optimal NPVC.For C prices under 40 $US MgC optimizing simultaneously for timber production and C sequestration is the best option, as additional although sub-optimal revenues can be obtained from C payments.Lengthening the rotation, avoiding thinnings, or reducing their intensity increase carbon storage in planted teak, although, under the analyzed scenarios, after 120 yr. almost all carbon has been re-emitted to the atmosphere.Additional keywords: heuristics, genetic algorithms, operations research, forest management planning, stand level model, carbon stocks.Abbreviations used: C (Carbon); GA (genetic algorithm); NPVW, NPVC, NPVT (net present value from the cash flows of timber (wood), carbon, and total); SEV (Soil (land) expectation value); dbh (diameter at 1.3 m from the ground); G (stand basal area); Gp (potential site carrying capacity in terms of G); SQ (site quality); R (rotation, harvest age); A (age); I (thinning intensity); Vob, Vub (overbark, underbark volume); gr (basal area growth rate); r (interest rate); harvest and transport costs (Hc); Pc (C price).

Sistema de crecimiento y rendimiento maderable para plantaciones de teca (Tectona grandis L. f.) en Campeche, México

Los modelos dinámicos de crecimiento y rendimiento maderable son importantes para tomar decisiones en el manejo forestal. Estos modelos predicen la dinámica futura en función de atributos del rodal y son herramientas prácticas para aplicar silvicultura en la planeación del manejo de bosques naturales y plantaciones. En México, teca (Tectona grandis L. f.) es de importancia maderable en plantaciones comerciales; sin embargo, las herramientas de este tipo para el manejo técnico y científico son limitadas. Se desarrolló un sistema de crecimiento y rendimiento maderable (Scrm) explícito para plantaciones de teca establecidas en Campeche, México. El Scrm se conformó de ecuaciones dinámicas de diferencia algebraica ajustadas al utilizar información dasométrica de una red de parcelas permanentes con remediciones. La selección de cada componente del Scrm se basó en un análisis de la bondad de ajuste y en una inspección gráfica para comparar la similitud entre el patrón generado y la tendencia observada, se buscó un balance entre consideraciones estadísticas y tendencias biológicas de crecimiento. La mortalidad se determinó a través de la densidad de plantación inicial y fue sensible al índice de sitio. Se seleccionaron sistemas de crecimiento tipo Schumacher para el área basal y el volumen. A la edad del turno planeado a 19 años y con un índice de sitio de 18 m, se estimaron rendimientos de 152.75 m3 ha-1, 136.86 m3 ha-1 y 113.12 m3 ha-1 para toda la plantación en general, para la densidad de 1250 plantas por hectárea (pl ha-1)y para la densidad de 816 pl ha-1, respectivamente. El Scrm generado permite estimar el volumen total con corteza por hectárea bajo las condiciones locales específicas de establecimiento, de manejo silvícola y de calidad de sitio de las plantaciones de teca analizadas.

Anatomical characteristics of <i>Tectona grandis</i> L.f from different sites in Mato Grosso state

The anatomical characteristics of the wood are influenced by the quality of the sites of the material provenance, which, consequently, leads to alterations in its physical and mechanical properties. The aim of this paper was to assess and characterize the organoleptic and anatomical properties of the teak (Tectona grandis) from different sites in the state of Mato Grosso, Brazil. Regarding the anatomical characteristics the length, width, diameter and the thickness of the wall for fiber were assessed; the length and diameter of the vessels; the length, width and frequency of the rays. The results obtained showed that the organoleptic properties do not present variations between the different sites. The effect of the site, where the teak plantation is established, produced significant variations in the parameters of the fibers (length, width of the fiber, lumen diameter and thickness of the wall) and in the rays (length, width and frequency). However, no significant vessel-related changes were seen.

The Effect of Manure Fertilizer Dose and Intercroppingon growth of 3 year old teak (Tectona grandis. L. f)

Planting system with one species continuously causes the degradation of land and the decline of plant productivity. It also occurs in teak (Tectona grandis L. f.) plantation. Application of manure in intercropping pattern was expected to improve the quality of the soil. This study a ims to determine the effect of manure on 3 y ears old teak productivity and to develop of site management model in silvicultural practices to increase the teak plantation productivity. This study used a completely randomized block design with 8 treatments, 4 replications and 100 plants for each plot. . Tree spacing was 3 x 3 meters. The parameters observed were high and diameter of teak. Statistical analysis used was variance analysis at the 0.05 and 0.01 level test. It was continued by a tendency or trend test for the treatment. The results showed that the manure application 30 tons/ha with intercropping gave the most positive growth compared to other treatments . Meanwhile, intercropping provides better plant compared to non-intercropped plants.

Interaction of abiotic factor on soil CO2 efflux in three forest communities in tropical deciduous forest from India.

Environmental factors along with soil physico-chemical properties play a significant role on the diurnal trend of soil CO2 efflux. Soil CO2 efflux in Indian tropical forests is poorly studied. We studied the soil CO2 efflux in a representative tropical deciduous forest at Katerniaghat Wildlife Sanctuary (KWLS), Uttar Pradesh. The three forest communities namely dry mixed (DMF), Sal mixed (SMF), and Teak plantation (TPF) were selected for measuring soil CO2 efflux in the summer season during April to May 2017 using automated LI-COR 8100 soil CO2 flux system. Soil physico-chemical parameters were also studied in the three abovementioned forest communities. We also measured the different microclimatic variables at forest understorey in all three communities during the summer season. Total day time soil CO2 efflux of 826.70, 1089.24, and 828.94 (μmolCO2 m-2d-1) was observed in TPF, SMF, and DMF respectively. Soil CO2 efflux observed significant differences (P < 0.01) among the three forest communities studied for the summer season in tropical deciduous forest of Terai Himalaya. Average soil CO2 efflux rate (μmol CO2 m-2 s-1) of 4.06 ± 0.36, 5.03 ± 0.45, and 4.37 ± 0.79 was observed in TPF, SMF, and DMF, respectively, which is positively correlated with total organic carbon (TOC) and water holding capacity (WHC) among soil physico-chemical variables. Among microclimatic variables, soil temperature (ST, °C) and air temperature (AT, °C) observed strong positive correlation with day time soil CO2 efflux in all three communities. Significant increase in soil CO2 flux was observed with increasing air and soil temperature (AT and ST) in DMF and SMF. Maximum TOC of 19.23 g Kg-1 was observed in SMF among all communities in the summer season. The result showed that soil CO2 efflux is closely associated with TOC, WHC, AT, and ST for Indian deciduous forest ecosystems.

Understanding the relationship between soil properties and litter chemistry in three forest communities in tropical forest ecosystem.

In this study, we investigated the relationship between soil properties and litter chemistry in three forest communities, i.e., Sal mixed forest (SMF), dry mixed forest (DMF), and teak plantation forest (TPF), in tropical deciduous forest ecosystem in North India. Fresh leaf litter and soil samples were collected at two soil depths (0-15 and 15-30 cm) from all these three forest communities. Litter bag experiment was also conducted to know differences in litter nutrients after its decomposition. The concentrations (mg kg-1) of different nutrients such as sodium (Na) 2.6, potassium (K) 38.5, calcium (Ca) 425, and carbon (C) 45.54% were highest in fresh litter collected from DMF. Total organic carbon (g kg-1) was significantly higher in SMF (19.23) in comparison to DMF (18.41) and TPF (13.61) at 0-15-cm soil depth. Na, K, Ca, available P, total P, available N, and total N were highest in DMF soil. We observed significantly positive correlation between all nutrients of litter and soil. Although soil bulk density (BD) and particle density (PD) showed their significant negative correlation with litter C, total porosity was positively correlated. Similarly, litter Na has its significant negative correlation with BD and positive correlation with PD. The litter chemistry played a significant role in changing soil pH and TOC. All litter nutrients, except total P, have their significant positive correlation with soil pH. Total P, C, and N of litter have their significant positive correlation with total soil organic carbon. This indicates that litter chemistry and soil properties have specific relation among them despite unique species composition in each forest community.

Investigating the contribution of climate variables to estimates of net primary productivity in a tropical deciduous forest in India.

Investigating the impact of climate variables on net primary productivity is crucial to evaluate the ecosystem health and the status of forest type response to climate change. The objective of this paper is (1) to estimate spatio-temporal patterns of net primary productivity (NPP) during 2001 to 2010 in a tropical deciduous forest based on the input variable dataset (i.e.meteorological and biophysical) derived from the remote sensing and other sources and (2) to investigate the effects of climate variables on NPP during 2001 to 2010. The study was carried out in Katerniaghat Wildlife Sanctuary that forms a part of a tropical forest and is situated in Uttar Pradesh, India, along the Indo-Nepal border. Mean annual NPP was observed to be highest during 2007 with a value of 878gCm-2year-1 and 781.25gCm-2year-1 for sal and teak respectively. A decline in mean NPP during 2002-2003, 2005 and 2008-2010 could be attributed to drought, increased temperature and vapour pressure deficit (VPD). The time lag correlation analysis revealed precipitation as the major variables affecting NPP, whereas combination of temperature and VPD showed dominant effect on NPP as revealed by generalized linear modelling. The carbon gain in NPP in sal forest was observed to be marginal higher than that of teak plantation throughout the study period. The decrease in NPP was observed during 2010, pertaining to increased VPD. Contribution of different climatic variables through some link process was revealed in statistical analysis and clearly indicated the co-dominance of all the variables in explaining NPP.

UJI LAMA PERENDAMAN STEK LADA (PIPER NIGRUM L) PADA EKTRAK TAUGE TERHADAP PERTUMBUHAN AKAR DAN TUNAS

The study was intended to determine the growth responseof the pepper plant steak due to an extended 3 hours of Tauge extracting with aconcentration of 300 ml/l. The design used in this study is a completely randomdesign with a single factory based pattern of P1 (1 hour), P2 (2 hours), P3 (3hours), P4 (4 hours), P5 (5 hours). Variable observations in this study are thenumber of shoots (strands), length of shoots (cm2), number of leaves (strands),amount of roots (cm2), length of roots (cm2), fresh shoots (gram), shoots dryweights (gram), root fresh weights (gram), root dry weights (gram), root dryweights (gram). Studies indicate that extended snorting time of pepper on andTauge extracting gives very real influence to the growth variable of sprouts(50,66%), root length (32,96%), leaves (58,88%), root length (45,14%), rootweight (57,72%), shoots (71,43%), shoots dry weight (65,73%). Thus thetreatment of Tauge extracts as one of the natural growth regulator plants inseeding with a concentration of 300 m/l water would be best submerged for 3hours to speed up the growth and remove the roots to achieve the best quality ofthe steed growth.

General estimation models for above- and below-ground biomass of teak (Tectona grandis) plantations in Thailand

To estimate above- and below-ground biomass in teak (Tectona grandis) plantations throughout Thailand, we developed general allometric relationships between tree size parameters (stem diameter and height) and tree biomass (of leaves, stems, and roots). Trees were harvested from 18 plantations within the native range of teak in Thailand and across the area covered by these plantations. Allometric equations for total above- and below-ground biomass showed no significant inter-site differences and high correlation coefficients (0.90–0.99). This similarity across sites may be due to similarities in wood density among different age and/or size of teak trees. The majority of previous biomass estimation models for teak trees gave higher estimated values for both above- and below-ground biomass, suggesting that they should not be applied within Thailand. To estimate belowground biomass using root: shoot ratio (RSR), we evaluated RSR among stands of various ages and sizes. We further identified differences in RSR between Thailand and other regions. Estimated RSR varied among stands and decreased significantly with stand age and average tree size. This relationship suggests that belowground biomass can be estimated from aboveground biomass using RSR. However, RSR values differed among countries and regions. In summary, general allometric equations and RSR value can be used to accurately estimate above- and below-ground biomass in teak plantations across Thailand.

Developing Allometric Equations for Teak Plantations Located in the Coastal Region of Ecuador from Terrestrial Laser Scanning Data

Traditional studies aimed at developing allometric models to estimate dry above-ground biomass (AGB) and other tree-level variables, such as tree stem commercial volume (TSCV) or tree stem volume (TSV), usually involves cutting down the trees. Although this method has low uncertainty, it is quite costly and inefficient since it requires a very time-consuming field work. In order to assist in data collection and processing, remote sensing is allowing the application of non-destructive sampling methods such as that based on terrestrial laser scanning (TLS). In this work, TLS-derived point clouds were used to digitally reconstruct the tree stem of a set of teak trees (Tectona grandis Linn. F.) from 58 circular reference plots of 18 m radius belonging to three different plantations located in the Coastal Region of Ecuador. After manually selecting the appropriate trees from the entire sample, semi-automatic data processing was performed to provide measurements of TSCV and TSV, together with estimates of AGB values at tree level. These observed values were used to develop allometric models, based on diameter at breast height (DBH), total tree height (h), or the metric DBH2 × h, by applying a robust regression method to remove likely outliers. Results showed that the developed allometric models performed reasonably well, especially those based on the metric DBH2 × h, providing low bias estimates and relative RMSE values of 21.60% and 16.41% for TSCV and TSV, respectively. Allometric models only based on tree height were derived from replacing DBH by h in the expression DBH2 x h, according to adjusted expressions depending on DBH classes (ranges of DBH). This finding can facilitate the obtaining of variables such as AGB (carbon stock) and commercial volume of wood over teak plantations in the Coastal Region of Ecuador from only knowing the tree height, constituting a promising method to address large-scale teak plantations monitoring from the canopy height models derived from digital aerial stereophotogrammetry.

Land use strongly influences soil organic carbon and bacterial community export in runoff in tropical uplands‐

AbstractRapid development and associated land‐use change have resulted in increased soil erosion and widespread land degradation in tropical ecosystems. Precipitation‐induced soil erosion causes the export of soil organic carbon (SOC) and the associated bacterial community affecting soil quality and functioning. We assessed the transfer of SOC and soil bacterial diversity and functions in surface water runoff from different land uses: Teak with and without understory (TW and TWO, respectively) and upland rice (UR) in a tropical, upland catchment during a simulated rain event. Total suspended sediment (TSS) concentration was higher in TWO (1.23 ± 0.21 g L−1) than in TW (0.37 ± 0.16 g L−1) and UR (0.44 ± 0.2 g L−1), whereas dissolved organic carbon (DOC) concentration was lower under TWO (3.8 ± 0.7 mg L−1) than under TW or UR (13.4 ± 7.5 and 9.57 ± 4.8 mg L−1, respectively). Runoff from TWO harboured the highest proportion of bacterial taxa common to soil (27% and 29.5%) as compared with TW (22.8% and 13%) and UR (17.3% and 7%) for both particle attached and free‐living fractions, respectively. Bacterial community export in surface runoff was driven by changes in DOC and TSS, suggesting that eroded soil particles simultaneously carry organic carbon and attached bacterial taxa in surface runoff. Consequently, the export of soil functional groups relating to organic carbon degradation and nitrogen cycle was higher under TWO than in TW or UR. Our results underline that teak plantations with unsustainable practices such as the removal of understory degrades soil functions and accelerates land degradation through soil erosion and surface runoff on the long term.

Comparison of some physical, mechanical and anatomical properties of smallholder plantation teak (Tectona grandis Linn. f.) from dry and wet localities of Ghana

Smallholder plantation teak (Tectona grandis Linn. F.) plays an important role in the socio-economic development of tropical countries. Published research on site differences with respect to anatomical, physical and mechanical properties of smallholder teak in Ghana is limited. This study compared and evaluated some physical, mechanical and anatomical properties of smallholder plantation teak trees grown in dry and wet localities of Ghana. Ages and diameters for the randomly selected trees were in the range 10–20 years and 16–47 cm dbh, respectively. Wood samples were prepared from three stem heights and three radial positions and were tested for air-dry density, bending strength (MoR), modulus of elasticity (MoE), maximum compression strength parallel to grain, shear strength and hardness, using BS standards. Heartwood proportion was evaluated on the basis of stem height and tree age. Site conditions, tree age, stem and radial positions were all important factors that influenced the wood traits investigated. Comparatively, the wet site had disproportionately low mean heartwood proportion but higher values in air-dry density, MoE, MoR, hardness and shear strength. Overall, the teak wood studied suffered a relatively low bending strength that limits its use to light construction. The smaller vessel diameter of teakwood from the dry site has implications for utilization; first, small vessel diameter presents resistance to sap conduction resulting in slower growth with higher heartwood proportion; second, in terms of finishing, it gives the wood smooth surfaces upon planing and polishing, and therefore contributing to its aesthetic value; third, during drying, dimensional stability of the wood may be assured with smaller vessels. The differences in wood traits observed between the two sites emphasize proper site selection for improved wood quality. Since the age of the teak trees accounted for significant variations of all the wood traits investigated, to ensure optimum economic returns, small teak plantation holders may have to delay the harvesting of teak trees for a few years.

Effect of Growth Rate on Wood Quality of Teak (Tectona grandis L.f.) Plnatations at Malsiripura, Kurunegala, Sri Lanka

This study was designed to find out how the quality of teak wood changes with growth rates. Based on the diameter at breast height and total tree height, three crown classes namely, suppressed, co-dominant and dominant were selectedfrom a 45-year-old state Tectona grandis Lf (teak) plantation at Malsiripura, Kurunegala, Sri Lanka. Three trees from each crown class were studied. Sample disks were extracted at breast height from each tree, to measure ring width whose values indicate growth rate and specific gravity of each ring. Percentage heartwood was also measured. Mean ring width and mean specific gravity values for each crown class were analyzed. Results indicated that there is no relationship between growth rate and specific gravity. Hence, fast growth rates in shorter rotations is unlikely to reduce specific gravity in teak. Woodproperty patterns werefound similar between the crown classes, indicating that these trends are inherent to teak. It was also found that the percentage heartwood is positively affected by growth rate.

Effect of Clone and Sites for Wood Properties of Fast Grown Teak and Determination of The Best Clone for Next Cultivation in Teak Plantation Industries

Cloning copies all of the characteristics of an individual, not just the optimal characteristics, and thus the clonal plantations have a vital role in increasing forest productivity. Determination of the surviving clone with the best properties in all plantation sites may assure uniformity in wood properties. Determination of the surviving clone with the best properties in all plantation sites may assure uniformity in wood properties. The more uniform the wood properties, the higher price the industries are willing to pay. This study aimed to investigate wood properties variation within and between selected clones at two different plantations of super teak, in order to investigate the effect of genetic or environment on wood properties and to determine the best clone for subsequent cultivation based on the wood properties. Research was conducted on three clones of 5-year old fast grown teak at two locations. The results showed that genetic factor more influenced the uniformity of wood color. Furthermore, site effect was more dominant on wood density, wood hardness, and radial unit shrinkage, while MOE, fibre length, and ‘crystallinity’ were affected by genetic effect. Effect of clone was not clear on radial and tangential shrinkage, tangential unit shrinkage and MOR. In the case of fast grown teak, Clone B can be recommended for future plantation at both sites.

Surface free energy of 10 tropical woods species and their acrylic paint wettability

The surface free energy (SFE) of woods and their wettability are important characteristic for wood painting. No information is available regarding the SFE and wettability of Indonesian tropical woods. The purpose of the study was to determine the SFE and wettability of 10 Indonesian tropical woods. The woods tested in this study were fast-growing species from plantation of teak, sengon, jabon, pine, and species from natural forest of ramin, meranti, mahagony, camphor, keruing, and ebony. Surface roughness was measured by a profilometer, while wettability was determined by sessile drop method. The SFE values were calculated based on the Rabel method. Wettability was characterized by constant contact angle change rate (K) using the Shi and Gardner (S/G) model. The results showed that the mean roughness (Ra) value of fast-growing species from plantation was 13.58 μm and of species from natural forest was 10.73 μm. The SFE of woods varied from 36.00 mJ/m2 in the Meranti to 69.68 mJ/m2 in the Sengon. It was observed that the Meranti wood with the lowest value of SFE provided the lowest value of K (0.01) which indicated the poorest in wettability. The Sengon wood with the highest value of K (0.06) should provide the best wettability for the acrylic paint.

Use of forest remnants and teak (Tectona grandis) plantations by small mammals in Mato Grosso, Brazil

ABSTRACTPlanted forests are replacing extensive areas of degraded pastures. It is extremely relevant for species conservation to understand how the community of small mammals responds to these changes. This study assessed the use of habitats in native remnants surrounded by a teak matrix by small mammals in the Cerrado, in the Pantanal and in the Amazon, in Mato Grosso state, Brazil. We used pitfall, Sherman and Tomahawk traps for sampling. The traps were installed at a distance of 50, 150 and 400 m from the edge of the fragment to the matrix, and the same design was used for the forest fragments. We recorded 22 species with 370 individuals of small mammals captured (13 rodents and nine marsupials), with a total effort of 14,350 conventional traps/night and 4,700 pitfalls/night. In this study, the teak plantation presented a barrier, preventing the dispersion of some species, especially Gracilinanus agilis, Marmosa demerarae, Philander opossum, Neacomys spinosus and Oecomys catherinae. Among the species that used the matrix, 10 were captured mainly up to 150 m from edges, suggesting a decrease in species richness as well as abundance within the matrix compared to remnants, indicating that remnants of native vegetation represent important refuges for small mammal biodiversity.

MANAGEMENT OF ECO-PESANTREN-BASED CRITICAL LAND DISASTER MITIGATION (CASE STUDY OF THE HIDAYATULLAH ISLAMIC BOARDING SCHOOL IN GUNUNG TEMBAK BALIKPAPAN KALIMANTAN)

This study aims to develop eco-pesantren-based critical land disaster mitigation management models. This study uses the theory of community-based disaster risk management). The method used is a qualitative research method by collecting data through field observations, interviews, documentation, and literature. This study concludes, first, the eco-pesantren-based critical land disaster mitigation management model, the fundamental environmental problems faced by Hidayatullah Islamic boarding school are as follows, namely: Threats of land damage, Forest damage, Threat of death of water sources. Second, management of critical land disaster mitigation carried out by the Hidayatullah pesantren, namely; the involvement of the pesantren academic community actively in solving environmental problems in the surrounding community of pesantren such as reforestation, by changing settlements in the form of wilderness and swamps to make the pesantren and surrounding areas green, creating artificial lakes, plantation land and agriculture where the santri cultivate, as well as cattle farms which are all managed by santri, the success of the Hidayatullah Islamic Boarding School in Balikpapan contributes clean water to the communities around the pesantren location. The Hidayatullah Islamic Boarding School moves its santri to organize the environment in the Gunung Tembak area. The development of Islamic boarding schools in agriculture is also an example for other pesantren. Where in the Hidayatullah Islamic Boarding School an agribusiness center was developed. On 40 hectares of critical land planted with sweet orange, lemon, zalacca, and melinjo. While the rest of the total land is 120 hectares in addition to educational land and settlements, gold teak plantations are developed. The ability of students in the field of agriculture is not only explored from self-taught abilities but also supported by training and courses

ANALISIS USAHA BUDIDAYA PEPAYA POLA AGROFORESTRI JATI-PEPAYA DI DESA PURWAHARJA, BANJAR

The utilization of land under tree stand in teak forest has been widely applied by Perhutani as a means to maintain the quality of teak tree and to give additional income to people living around the teak plantation. In general, the utilization of land under tree stand is by planting crops for limited duration. One of the crops planted under teak stands is papaya that is planted together with teak seedlings until 2 years. This study aims to analyze the feasibility of papaya cultivation under teak stands in Purwaharja Village, Banjar City. The analysis tools used include NPV (Net Present Value) and BCR (Benefit Cost Ratio). The results of this study show that the papaya cultivation under teak stands give NPV of IDR 20,072,606.- and BCR of 2.89. Therefore, the cultivation of papaya under teak stand is feasible to conduct.

Evaluation of Farmer’s Woodlots: A Common Agroforestry System Used to Establish Forest Plantations

Farmer’s woodlot is a common agroforestry system used to establish forest plantations while increasing farmer’s income and proper utilization of marginal lands. This study was conducted to evaluate the farmer’s woodlots established in dry and intermediate zones of Sri Lanka. 17 teak plantations were selected from three districts. Three farmer’s woodlots from each plantation were randomly selected for the data collection and 170 farmers were interviewed using a questionnaire survey. dbh and total height were measured for the trees and soil samples were collected to determine organic carbon, nitrates, phosphorus, potassium, magnesium and calcium. Growth of teak in farmer’s woodlots was less than the average growth rates of the yield tables. Soil nutrients were present at very low levels and calcium was detected only in four plantations. Nitrate, potassium and magnesium were significantly different between the selected plantations and only nitrate was significantly correlated with teak growth. All farmers requested to extend the present 25-year land lease agreement to earn more income from teak. Poor site quality, damage caused by wild elephants, fire, insects and pests were common so that both timber growth and the yield of seasonal crops was low. Lack of technical support was also highlighted.

Does fluctuation of meteorological conditions across years influence stand transpiration of Tectona grandis plantation?

AbstractTectona grandis (teak) is widely planted as high‐quality timber in the seasonal tropics, yet detailed data on its seasonal water use and the effect of climatic fluctuations on its transpiration behaviour are limited. We measured sap flux density (SFD) using Granier's sap flow sensors for three wet and two dry seasons in the years 2012, 2014, and 2015 (wet season only) in 7 to 14 trees and made a calibration of Granier's equation for teak to calculate SFD for estimating whole‐tree water consumption and stand‐level transpiration. We also characterized the effects of daily rainfall, vapour pressure deficit, and photosynthetically active radiation on the daily SFD of individual trees. We found a large fluctuation in rainfall in the wet seasons of 2012 to 2015 (1,159 mm in 2012, 778 mm in 2014, and 727 mm in 2015). Total wet and dry season stand‐level transpiration were 824 and 501 mm in 2012 and 446 and 214 mm in 2014, respectively, whereas the wet season transpiration of 2015 was 358 mm. Namely, reduced wet season rainfall reduced the total stand‐level transpiration of teak at the study site. Most variations in daily SFD were due to differences in meteorological conditions, that is, day‐time mean vapour pressure deficit, photosynthetically active radiation, and daily rainfall associated with the seasons of particular year. We also established models to estimate the stand‐level transpiration of a teak plantation. The findings of the present study could be useful for forestation program and hydrological management in tropical regions with seasonal drought.