Logged-over Forest Research Articles

Greenhouse gas emissions during plantation stage of palm oil-based biofuel production addressing different land conversion scenarios in Malaysia.

The environmental impacts with regard to agro-based biofuel production have been associated with the impact of greenhouse gas (GHG) emissions. In this study, field GHG emissions during plantation stage of palm oil-based biofuel production associated with land use changes for oil palm plantation development have been evaluated. Three different sites of different land use changes prior to oil palm plantation were chosen; converted land-use (large and small-scales) and logged-over forest. Field sampling for determination of soil N-mineralisation and soil organic carbon (SOC) was undertaken at the sites according to the age of palm, i.e. <5years (immature), 5-20 and >21years (mature oil palms). The field data were incorporated into the estimation of nitrous oxide (N2O) and the resulting CO2-eq emissions as well as for estimation of carbon stock changes. Irrespective of the land conversion scenarios, the nitrous oxide emissions were found in the range of 6.47-7.78kg N2O-N/ha resulting in 498-590kg CO2-eq/ha. On the other hand, the conversion of tropical forest into oil palm plantation has resulted in relatively higher GHG emissions (i.e. four times higher and carbon stock reduction by >50%) compared to converted land use (converted rubber plantation) for oil palm development. The conversion from previously rubber plantation into oil palm plantation would increase the carbon savings (20% in increase) thus sustaining the environmental benefits from the palm oil-based biofuel production.

PERMUDAAN ALAMI DALAM HUTAN BEKAS TEBANGAN DI SEKUNDUR, SUMATRA UTARA

A phytososiological analysis of saplings was made using quadrate method in the six years old logged-over forest at Sekundur, North Sumatra. The results showed that within 0.2 hectare plot, 123 species belonging to 79 genera and 36 families were recorded. Three community types were recognized, i.e. Agrostistachys longifolia - Teijsmanniodendron sarawakanum, Macaranga hypoleuca - Macaranga pruinosa and Endospermum malaccensis - Macaranga javanica communities. The structure and floristic composition of each community varies and they were related primarily with the forest distur¬bance. There were found that the number of both species and individuals of sapling decreased with increasing of the forest disturbance

SOIL FUNGAL COMMUNITY ASSOCIATED WITH PEAT IN SARAWAK IDENTIFIED USING 18S rDNA MARKER

Fungi are principal decomposing microorganisms in acidic environment of peatlands. A useful tool for molecular screening of soil fungal communities using the 18S rDNA primer has been proven capable of identifying a broad range of fungi species within Ascomycota, Basidiomycota, Zygomycota and Chytridiomycota. Currently, very little information is available on fungal communities in deep peat of Sarawak, Malaysia. In this study, we have isolated the fungi from soil samples taken in deep peat forests and oil palm cultivated areas. The fungal identity was undertaken using 18S rDNA primer which is EF4-F/fung5-R. The microscopic structures were conducted to confirm the identity of the isolates. Based on this study, the fungal division most commonly found in deep peat is the Ascomycota. Aspergillus fumigatus was the most common species and more dominant in oil palm cultivated areas and logged-over forest than in primary forest. In the primary forest, the dominant species was the A. flavus, while Hypocrea atroviridis was commonly associated with oil palm cultivated areas and logged-over forest. Other species of fungi isolated in peat primary forests were Penicillium chrysogenum, Trichoderma sp., Phanerochaete sp., Mortierella chlamydospora, A. niger, A. alliaceus, etc. The in-depth difference in the fungal communities for the different sites will be further investigated using the next generation sequencing technology.

The potential of rubber and acacia plantations for forest carbon stocks in Malaysia

In Malaysia, the primary forested land change process is due to the establishment of plantations on logged-over forests and areas used for shifting cultivation. While standing carbon stocks of natural forest have been the focus of many studies, reports on the carbon stocks in Acacia and rubber plantations in Malaysia is sparse. Therefore, this article attempts to collate and analyse Malaysian datasets on total carbon stocks for aboveground biomass in the Acacia and rubber plantations by applying the biomass expansion factor for the period from 1990 to 2013. The forest plantations have higher growth rates, and the harvesting waste and residues left behind are significantly more than the natural forests. Therefore, it leads to greater emission compared to the natural forests. Hence, Acacia and rubber plantations were not able to sequester and store carbon at the same amount as the natural forest, which resulted in carbon credit on the forest carbon stock.

Estimating Logged-Over Lowland Rainforest Aboveground Biomass in Sabah, Malaysia Using Airborne LiDAR Data

Unprecedented deforestation and forest degradation in recent decades have severely depleted the carbon storage in Borneo. Estimating aboveground biomass (AGB) with high accuracy is crucial to quantifying carbon stocks for Reducing Emissions from Deforestation and Forest Degradation-plus implementation (REDD+). Airborne Light Detection and Ranging (LiDAR) is a promising remote sensing technology that provides fine-scale forest structure variability data. This paper highlights the use of airborne LiDAR data for estimating the AGB of a logged-over tropical forest in Sabah, Malaysia. The LiDAR data was acquired using an Optech Orion C200 sensor onboard a fixed wing aircraft. The canopy height of each LiDAR point was calculated from the height difference between the first returns and the Digital Terrain Model (DTM) constructed from the ground points. Among the obtained LiDAR height metrics, the mean canopy height produced the strongest relationship with the observed AGB. This single-variable model had a root mean squared error (RMSE) of 80.02 t ha-1 or 22.31% of the mean AGB, which performed exceptionally when compared with recent tropical rainforest studies. Overall, airborne LiDAR did provide fine-scale canopy height measurements for accurately and reliably estimating the AGB in a logged-over forest in Sabah, thus supporting the state's effort in realizing the REDD+ mechanism.

Aboveground carbon stocks in oil palm plantations and the threshold for carbon-neutral vegetation conversion on mineral soils

The carbon (C) footprint of palm oil production is needed to judge emissions from potential biofuel use. Relevance includes wider sustainable palm oil debates. Within life cycle analysis, aboveground C debt is incurred if the vegetation replaced had a higher C stock than oil palm plantations. Our study included 25 plantations across Indonesia, in a stratified study design representing the range of conditions in which oil palm is grown. From allometric equations for palm biomass and observed growth rates, we estimated the time-averaged aboveground C stock for 25-year rotation and 95%-confidence interval to be 42.07 (42.04–42.10) Mg C ha−1 for plantations managed by company on mineral soils, 40.03 (39.75–40.30) Mg C ha−1 for plantations managed by company on peat, and 37.76 (37.42–38.09) Mg C ha−1 for smallholder oil palm on mineral soils. Oil palm can be established C debt-free on mineral soils with aboveground C stocks below these values; neutrality of mineral soil C pools was documented in a parallel study. Acknowledging variation in shoot:root ratios, the types of vegetation that can be converted debt-free to oil palm include grasslands and shrub, but not monocultural rubber plantations, rubber agroforest, and similar secondary or logged-over forests of higher C stock.

Error in the estimation of emission factors for forest degradation in central Africa

The implementation of forest-based projects to mitigate greenhouse gas emissions requires the estimation of emission factors (here the difference in biomass stocks between two forest types). The estimation of these quantities using forest inventory data and allometric models implies different sources of errors that need to be prioritized to improve the precision of estimation. Using data from permanent sample plots in a tropical moist forest in central Africa and considering four allometric models with equal likelihood, the largest source of error in the estimate of the difference of biomass between intact and logged-over forest was that due to the model choice (40 % of the sum of squares). The error due to the model choice did not cancel out in the difference due to an interaction between the model's prediction and the diameter structure of the forest. The variability in biomass between plots was the second largest source of error, but was underestimated because of post-stratification. The error due to the model choice could be reduced by weighting the models' predictions.

Ecosystem Services and Biodiversity in a Rapidly Transforming Landscape in Northern Borneo

Because industrial agriculture keeps expanding in Southeast Asia at the expense of natural forests and traditional swidden systems, comparing biodiversity and ecosystem services in the traditional forest–swidden agriculture system vs. monocultures is needed to guide decision making on land-use planning. Focusing on tree diversity, soil erosion control, and climate change mitigation through carbon storage, we surveyed vegetation and monitored soil loss in various land-use areas in a northern Bornean agricultural landscape shaped by swidden agriculture, rubber tapping, and logging, where various levels and types of disturbance have created a fine mosaic of vegetation from food crop fields to natural forest. Tree species diversity and ecosystem service production were highest in natural forests. Logged-over forests produced services similar to those of natural forests. Land uses related to the swidden agriculture system largely outperformed oil palm or rubber monocultures in terms of tree species diversity and service production. Natural and logged-over forests should be maintained or managed as integral parts of the swidden system, and landscape multifunctionality should be sustained. Because natural forests host a unique diversity of trees and produce high levels of ecosystem services, targeting carbon stock protection, e.g. through financial mechanisms such as Reducing Emissions from Deforestation and Forest Degradation (REDD+), will synergistically provide benefits for biodiversity and a wide range of other services. However, the way such mechanisms could benefit communities must be carefully evaluated to counter the high opportunity cost of conversion to monocultures that might generate greater income, but would be detrimental to the production of multiple ecosystem services.

Mortality and Ingrowth Pattern of Dipterocarps in Forest Recovery in East Kalimantan

In primary and logged-over natural forest, the stand conditions such as stand structure, mortality and ingrowth rates will vary according to the species characteristic. The study objective was to determine mortality and ingrowth/recruitment rates to formulate biometric characteristic variability of dipterocarps forest in logged-over forests based on time series data. The study site was located in Labanan, East Kalimantan Province. Permanent measurement plots within logged-over forest were located to represent threedifferent logging techniques, i.e., (a)reduced impact logging with limit diameter 50 cm (RIL 50), (b) RIL 60, (c) conventional logging and (d) primary forest as control. Total plot permanent area about 48 ha that measured 2 years periodically along 17 years after logging.  Data analysis of stands were divided into two major groups, i.e., Dipterocarps and non Dipterocarps. The mortality rates on logged forest were 2.5-29.3% ha-1 2yr-1 then very closed to primary forest after the 5th year after logging. While the ingrowth rate in logged forest were 1.3 – 21.3% ha-1 2yr-1 that have higher value than the primary forest along 17 years. The mortality and ingrowth rates fluctuation of Dipterocarps species group having different pattern with non Dipterocarps.  Keywords: Dipterocarps, logged-over forest, mortality, ingrowth

Population Structures of Four Tree Species in Loggpopulation Structures of Four Tree Species in Logged-Over Tropical Forest in South Papua, Indonesia: an Integral Projection Model Approach

Selective logging has been taking place in Papua for several decades. In contrast, very little is known about the stand structure in post-logged forest. Hence, this paper investigates stand structures in logged-over area of tropical forest in South Papua. Four species were selected in three one-hectare permanent sample plots (PSPs): Vatica rassak, Syzygium sp, Litsea timoriana and Canarium asperum. PSPs were located in the forest concession area of PT. Tunas Sawaerma in Assiki, Boven Digul, in South Papua. Data sets comprised measurements made in 2005 and 2012 consisting of species, diameter at breast height (DBH), mortality and number of tree of each species. Integral Projection Models (IPMs) were developed, taking into account mortality, growth, recruitment and fecundity. Results show the pattern of stand structures of the four species were more or less similar, i.e. more individual trees were present in the small diameter classes than in the larger diameter classes. The general pattern of the individual distribution of the four species is the typical reverse-J shape. Syzygium sp. has a greater number of individuals in the small diameter classes than the other three species. Population growth rates (λ) are above one, indicating that the stand structures of the population dynamics of the four species are recuperating. Conclusively, these results suggest that species composition and population structure in these logged-over forests are recovering increasingly.

Impact of Nitrogen Fertilizer Application on Nitrous Oxide Emission in Oil Palm Plantation

This study investigates the impact of N-fertilizer application on the emission of nitrous oxide (N2O) in oil palm plantations. The soil sampling was undertaken at three different oil palm plantations of different land use, i.e. transformed land use (large and small-scale) and a logged-over forest. The soil samples were analysed for N, P and K contents and soil organic carbon. It was found that despite different amount of N-fertilizer applied at the plantations (in the range of 99-155kg N/ha), immature palm development seems to release relatively higher amount of N2O compared to mature stage. However, further estimation of carbon equivalent emission (CO2-eq) would be a more useful means for estimating the impact of N-fertilizer on greenhouse gas emission.

English

Selective logging has been taking place in Papua for several decades. In contrast, very little is known about the stand structure in post-logged forest. Hence, this paper investigates stand structures in logged-over area of tropical forest in South Papua. Four species were selected in three one-hectare permanent sample plots (PSPs): Vatica rassak , Syzygium sp, Litsea timoriana and Canarium asperum . PSPs were located in the forest concession area of PT. Tunas Sawaerma in Assiki, Boven Digul, in South Papua. Data sets comprised measurements made in 2005 and 2012 consisting of species, diameter at breast height (DBH), mortality and number of tree of each species. Integral Projection Models (IPMs) were developed, taking into account mortality, growth, recruitment and fecundity. Results show the pattern of stand structures of the four species were more or less similar, i.e. more individual trees were present in the small diameter classes than in the larger diameter classes. The general pattern of the individual distribution of the four species is the typical reverse-J shape. Syzygium sp. has a greater number of individuals in the small diameter classes than the other three species. Population growth rates (λ) are above one, indicating that the stand structures of the population dynamics of the four species are recuperating. Conclusively, these results suggest that species composition and population structure in these logged-over forests are recovering increasingly.

A trait-based trade-off between growth and mortality: evidence from 15 tropical tree species using size-specific relative growth rates.

A life-history trade-off between low mortality in the dark and rapid growth in the light is one of the most widely accepted mechanisms underlying plant ecological strategies in tropical forests. Differences in plant functional traits are thought to underlie these distinct ecological strategies; however, very few studies have shown relationships between functional traits and demographic rates within a functional group. We present 8 years of growth and mortality data from saplings of 15 species of Dipterocarpaceae planted into logged-over forest in Malaysian Borneo, and the relationships between these demographic rates and four key functional traits: wood density, specific leaf area (SLA), seed mass, and leaf C:N ratio. Species-specific differences in growth rates were separated from seedling size effects by fitting nonlinear mixed-effects models, to repeated measurements taken on individuals at multiple time points. Mortality data were analyzed using binary logistic regressions in a mixed-effects models framework. Growth increased and mortality decreased with increasing light availability. Species differed in both their growth and mortality rates, yet there was little evidence for a statistical interaction between species and light for either response. There was a positive relationship between growth rate and the predicted probability of mortality regardless of light environment, suggesting that this relationship may be driven by a general trade-off between traits that maximize growth and traits that minimize mortality, rather than through differential species responses to light. Our results indicate that wood density is an important trait that indicates both the ability of species to grow and resistance to mortality, but no other trait was correlated with either growth or mortality. Therefore, the growth mortality trade-off among species of dipterocarp appears to be general in being independent of species crossovers in performance in different light environments.

The Effect of Silvicultural Treatment on Stand Growth of Logged-Over Forest in South Papua

Forest stand structure could be used as one of the variables in deciding the possibility to harvest forest product. On logged-over forests, data and information over stand structure could become the basis for decision making for harvesting. To measure and analyze yield on logged-over forest, each forest management unit (IUPHHK) is obligated to establish Permanent Sample Plots (PSPs) for monitoring the growth and yield of the managed stand. In some of the plots, maintenances and thinning treatments are applied while other plots are not treated. The results, after several years of observations, showed that there was a difference in stand structure (tree number) of each diameter class both in plots with treatment and without treatment. The rate of in-growth, up-growth and mortality varied between plots without and with treatment in each diameter class and length of time after harvesting. The average diameter increment of trees in the stands of the untreated plots was higher (0.60 cm yr -1 ) compared to the treated plots (0.55 cm yr -1 ).

Regeneration in canopy gaps of tierra-firme forest in the Peruvian Amazon: Comparing reduced impact logging and natural, unmanaged forests

Reduced impact logging (RIL) has been promoted as a cornerstone in sustainable forest management in the tropics, although the ecological implications of RIL guidelines are poorly understood. This study aims to identify the impact of RIL on the regeneration of commercial timber species by comparing the regeneration dynamics of logging gaps with naturally occuring canopy gaps. In the concession of Consorcio Forestal Amazonico in the region of Ucayali in the Peruvian Amazon, a total of 210 circular sample plots were established in 35 gaps in unmanaged natural forest and 35 canopy gaps in forest managed according to RIL guidelines. The size of each canopy gap was estimated by establishing a polygon that followed the vertical projection of the edge of the gap. Three circular plots of 100 m2 were established within each canopy gap. The center points of the plots were placed at the stump, mid-trunk and crown of the fallen tree. It appeared that the total abundance of seedlings did not differ significantly between logging gaps and natural canopy gaps. Instead the response to logging varied between species groups. The Clarisia sp. species group had a significant negative response to logging, while Ormosia sp., Aniba sp., Ocotea sp., Qualea sp. and Terminalia sp. were significantly more abundant in gaps of logged-over forest. A direct effect of seed tree retention on seedling abundance could not be detected statistically. Possible reasons for observed differences between untouched and logged forest and consequences of observed patterns for long-term forest development and management were discussed. It was concluded that issuing and enforcing strict guidelines on sustainable forest management is no guarantee for preserving species composition in tropical forests.

Low carbon emission development strategies for Jambi, Indonesia: simulation and trade-off analysis using the FALLOW model

Economic growth in rural areas has to align with preservation of land uses that optimise environmental services. This means that trade-offs between economic and ecological priorities need to be understood, quantified and managed. We aimed to estimate the trade-off in the Tanjung Jabung Barat district of Jambi province Indonesia, where traditional agroforestry systems on both peat and mineral soils and logged-over forests give way to monocultural plantations of pulpwood and oil palm (Elaeis guineensis). Simulations of a 30-year time period of four scenarios using the FALLOW (Forests, Agroforests, Low-value-Landscape, Or, Wastelands) model show that a business-as-usual scenario of economic growth unhindered by the application of conservation scenarios will lead to high carbon dioxide CO2 emissions. The forest and agroforest protection scenario, with moderate assumptions for peat-based emissions, had opportunity costs of 3–100 USD/t CO2e. This occurred especially when the establishment of oil palm plantations, which are currently the most profitable land use option in the area, is directed solely to under utilized mineral soils. The high trade-off values are difficult to reconcile when relying only on C trading mechanism to offset economic opportunity costs of not converting forests and/or agroforests to plantations. We conclude that law-based protection of existing forests, investment in intermediate intensity agroforestry options that utilize locally adapted trees and do not require drainage of peatlands, and re-introduction of tapping Jelutung (Dyera sp) latex as non-timber peat forest product, are needed in the Tanjabar district to provide options that are sustainable from both ecological and economic perspectives.

Growth of &amp;lt;i&amp;gt;Shorea contorta&amp;lt;/i&amp;gt; Vid. Inoculated with Eucalypt Ectomycorrhizal Fungi in the Nursery and in a Logged-Over Dipterocarp Forest in Surigao, Philippines

This study was conducted to determine the compatibility of ectomycorrhizal (ECM) fungi associated with eucalypts on dipterocarps. Two nodal cuttings of Shorea contorta (Vid.) were rooted in a non-mist system for two months, and later inoculated with vegetative mycelia of three strains of Pisolithus collected under eucalypts and a strain of Scleroderma from dipterocarps. Inoculated rooted cuttings were planted in irradiated potting mix and raised in the nursery for five months. Root colonization prior to outplanting ranged from 31% to 38% and ECM fungi did not colonize the uninoculated ones. The cuttings were outplanted in a logged-over dipterocarp forest in Bislig, Surigao Sur following a Randomized Complete Block Design with four blocks; each block was planted with 50 seedlings. Two years after outplanting, Pisolithus strain from New Caledonia (H6394) promoted the highest height (46 cm) and diameter (0.48 cm) increment. Height was increased by 17% and diameter by 7% relative to the uninoculated control. By contrast, Pisolithus strain from the Philippines (H615) gave the shortest (26 cm) height increment and smallest (0.42 cm) diameter. Diameter growth of cuttings inoculated with Scleroderma D01 (from the Philippines) and a Pisolithus strain from Australia (H445) was bigger (0.47 cm) than the uninoculated treated cuttings (0.45 cm). In terms of survival, the uninoculated cuttings gave the highest (90%) percent survival while the lowest (60%) was those inoculated with Pisolithus strain from New Caledonia. It is possible that the indigenous ECM fungi infected easily the roots of the uninoculated cuttings thus contributing to the high survival rate (90%). During outplanting, fruit bodies of S. columnare were present in the field site. The results, however, show that ECM fungi were able to colonize the roots and that some strains promoted the growth and survival of S. contorta planted in a logged-over dipterocarp forest in Bislig, Surigao, Philippines.

English

Although, soil properties of tropical rainforest in Southeast Asia have been characterized by several researchers, limited information exists on soil characteristics due to conversion of natural forest into various land use types such as oil palm plantation, rubber plantation, forest plantation and secondary forest. A study was conducted to characterize the soil properties under various land use types of logged-over forest (LF), rehabilitation forest (RF), oil palm (OP) and rubber plantation (RP) at Universiti Putra Malaysia, Bintulu, Sarawak, Malaysia. Soil profiles were dug up to 100 cm depth and 50 cm width and were followed by soil sampling according to soil horizon. Soil morphology was determined in the field while soil physico-chemical properties were determined in the laboratory using standard soil analysis. The soils at RF, LF, OP and RP were derived from sandstone intercalated with shale which gives silty loam and sandy clay loam texture. The soils are acidic to weakly acidic with pH increases with depth. The Cation Exchange Capacity (CEC) and Total Carbon (TC) of soils tend to decrease with depth and it seems to be higher under OP and RP as compared to RF and LF. The Alo, Ald, Feo and Fed increased with depth in all of the profiles. The values of Point Zero of Salt Effect (PZSE) and &sigma;p are low in all sites with dominated by kaolin minerals and sesquioxide properties indicating that the soils are highly weathered and low soil fertility status. &nbsp; Key words:&nbsp;Forest rehabilitation, logged-over forest, oil palm and rubber plantation, charge characteristic.

Measuring the Short-term Success of Hill Dipterocarp Forest Restoration: The Use of Organic Materials

Restoring degraded logged-over forest which is indicated by low in soil fertility and organic matter due to imbalance nutrient cycle are of paramount importance as there has been increasing attention towards these forests as the sustainable use of these resources. Forest restoration through reintroduces tree species lost, especially fast growing dipterocarp is implemented to curtail degraded logged-over forest and improve the soil fertility through organic material application is important, but only few information is available on restoration of degraded forest. The objectives of this study were: (1) to evaluate the growth and biomass accumulation on different kind and application rate of organic materials; and (2) to determine suitable application for restoration of degraded forest in the humid tropics of Peninsular Malaysia. This study was conducted at Shorea leprosula stand in Tekai Forest Reserve, Pahang, Malaysia. To evaluate the effects of organic materials on survival, growth and biomass increment, mineral soils were amended with different application rates of organic materials, such as pulp mill sludge, compost, oil palm mesocarp and their combinations. Application rate of each organic materials were 0, ?, ½, ?, and ¾ of v/v. Growth measurement was conducted in every month for early growth up to 3 months after application and continued for every three months, while biomass accumulation were measured on initial, 3-, 6- and 12-month after application by destructive sampling method. Plant growth and biomass accumulation was increased by all amendments, however their rates was decreased during early growth as a result of adaptation process. Up to 12 months analyses, the best diameter growth performance appeared by compost 66.67% (treatment 9) and combination 33.33% (treatment 17), followed by treatment 10 (compost 75%) and 18 (combination 50%), while the best height growth performance appeared by treatment 18 and 17 and followed by treatment 9. The biggest biomass increment was on treatment 9, followed by treatment 18 and 17. The treatment that should be avoided for restoration program were control (treatment 1; only mineral soil), all application rates of pulp mill sludge and mix organic materials which high rate of sludge. Root formations on sludge medium shown in broken-down condition since they absorb water and dissolved minerals from pulp mill sludge medium, moreover all leaves shown unhealthy and burned down. Restoration program in tropical degraded forest land without applied organic material indicated poor growth rate and biomass accumulation, then organic material application to be one of the requirement treatments needed for better results. Compost as well as the type of past forest structure were important factors which resulted the best growth performance with high survival rate and recommended for restoration technique in Tekai Forest Reserve, Pahang, Malaysia or other comparative areas.

Ecological significance of the patches dominated by pioneer trees for the regeneration of dipterocarps in a Bornean logged-over secondary forest

Logging has created mosaics of Macaranga-dominated patches in mixed dipterocarp forests throughout Borneo. We questioned if the recruitment of dipterocarp seedlings is retarded within such Macaranga patches versus non-Macaranga patches, and if so, what mechanisms are involved. We determined the spatial pattern of dipterocarp saplings in a 4-ha plot established in a 12-year old logged-over forest, where Macaranga patches admix with non-Macaranga patches. The Iwao’s ω index demonstrated that the extant dipterocarp saplings were distributed exclusively with Macaranga patches at the beginning of our survey. We also monitored the survival of naturally dispersed dipterocarp seeds after a masting event. Seed supplies and germination occurred throughout the plot. The survival of naturally recruited seedlings decreased in Macaranga patches compared with non-Macaranga patches based on a GLMM analysis. Herbivory on the first pair of leaves did not affect the seedling survival, suggesting no contribution of herbivores to the decreased survival of seedlings in Macaranga patches. Net N mineralization rate and the concentration of bicarbonate soil Pi and Po were significantly lower in Macaranga patches than in non-Macaranga patches, while other abiotic factors such as soil water content, soil bulk density, and relative light intensity were not significantly different with each other. These results suggest that Macaranga patches limit the recruitment of dipterocarp seedlings through the impoverishment of soil nutrients. The lower N and P availability in Macaranga patches was possibly caused by the slow accumulation of soil organic matter under Macaranga trees because of the rapid decomposition of their litter.