Logged-over Forest Research Articles

Towards the Assessment of Skid Trails in Logged-over Forest Using Drone Technology: A Review for the Timber Industry in Malaysia

Towards the Assessment of Skid Trails in Logged-over Forest Using Drone Technology: A Review for the Timber Industry in Malaysia

Impact of Malayan Uniform System and Selective Management System of Logging on Soil Quality in Selected Logged-over Forest in Johor, Malaysia

Understanding the effects of various forest management systems, including logging practices, on soil properties is essential for implementing sustainable management strategies. In Malaysia, two types of forest management systems were commonly used: Malayan Uniform System (MUS) and Selective Management System (SMS) practices. However, their effects on soil quality remained elusive, especially after decades of recovery. To address this need, we selected three plots for the MUS and SMS in Johor, Malaysia, to assess soil properties in logged-over forest plots. All the plots were natural forest reserves. Soil properties analyzed include soil acidity, electrical conductivity, cation exchange capacity, selected nutrient contents, and soil compaction. Generally, the results of the study indicate that forests logged using the SMS exhibit superior soil quality compared to those logged using the MUS according to several key soil properties. Specifically, significantly higher cation exchange capacity, potassium content, calcium content, and magnesium content with lower soil compaction was observed in the SMS when compared to MUS plots. In short, the SMS enhances soil quality more effectively than the MUS, even with a shorter logging cycle. This is because the SMS does not harvest all trees and distributes the impact of harvesting more evenly over time, rather than concentrating it at a single time point. Ultimately, this highlights that the SMS can play a significant role in promoting sustainable forest management practices by preserving soil quality.

Detecting canopy openings in logged-over forests: a multi-classifier analysis of PlanetScope imagery

This study focused on the detection of forest canopy openings resulting from harvesting activities in hill tropical forests. Canopy openings, whether natural or human-induced, can have detrimental effects on forest ecosystems. Traditional ground surveys to assess the extent of canopy opening can be challenging and time-consuming. Therefore the study aimed to utilise satellite imagery, specifically PlanetScope data, to detect, map and measure canopy openings in logged-over forests. Three different classification algorithms, namely maximum likelihood classifier (MLC), support vector machine (SVM) and object-based image analysis (OBIA) were used and compared to identify canopy opening areas. The assessment was conducted in two stages: a preliminary assessment with three classes (forest, canopy opening and shadow) and a final assessment with two classes (forest and canopy opening). The overall accuracies of the classification algorithms were 82% for MLC, 91% for SVM and 90% for OBIA. Both SVM and OBIA surpassed the accuracy threshold, with SVM being the most effective in detecting and extracting canopy openings in dense forests. Results demonstrated the potential of PlanetSope imagery and advanced classification algorithms to detect canopy openings in logged-over forests. The findings highlighted the importance of regular updates on canopy opening extent, particularly concerning sustainable forest assessment and minimising the negative impacts on forest ecosystems.

An alternative Silvicultural approach in managing logged-over forests

Based on the reality of production forest management so far, logged-over forest improvement activities generally have received less attention, giving rise to the notion that the management of logged-over areas is not being taken seriously. In general, regeneration and maintenance of remaining stands as a component of the silvicultural system has not been carried out. Silviculturists must address these developments and respond to rapidly changing expectations and global paradigm shifts in how forests are viewed. Silviculturists are challenged to develop silvicultural practices, including silvicultural systems that support the function and dynamics of forest ecosystems, and maintain biodiversity and ecosystem resilience while providing needed wood and non-timber products. In the context of production forest management, the adaptation differences of commercially valuable species in terms of their position in the natural vegetation development stage can be used as a consideration in the development of silvicultural system determination. Thus, the choice of silvicultural system to be applied reflects the condition of the forest. Alternative silvicultural approaches are characterized by several aspects, including selective cutting, diversity, and combination of mixed species with natural regeneration, and avoidance of intensive site-preparation methods.

Orangutan (Pongo pygmaeus ssp. wurmbii) ranging pattern in Punggualas, Sebangau National Park, Central Kalimantan Indonesia

Punggualas lies in the western part of Sebangau National Park (SNP). It is a logged-over forest, yet it is one of the major strongholds for the P. p. wurmbii population in the SNP. The range size, as well as the ranging pattern for Punggualas, has never been conducted. The study aimed to estimate orangutan ranging size and pattern as well as their distribution over the Punggualas forest. Ranging data within the area of interest (AOI) was collected from Feb 2015 – Dec 2019 (P1), and Mar 2020 – May 2022 (P2). Minimum convex polygon (MCP), range size of orangutan individual was calculated using adehabitatHR package in RStudio 4.1.1 for Windows. We visualized the distribution in ArcGIS 10.5 with Kernel Density (KD) tool. The range size of Mother-Infant is the greatest (259,6 Ha) among all individuals being studied within the study periods. Moreover, the size estimation was found greater in Mother-Infant sex class compared to other orangutan studies areas, such as Peat Natural Laboratory, and CIMTROP-UPR which reported a flanged male HR Size reaching 250 Ha per annum. We have found that the ranging pattern significantly changes over the study period. However, during P1, the distribution area was located within the northern of AOI, while in the P2 have changed to the south-eastern part of the AOI. We concluded that the ranging pattern indeed follows the fruit availability as well as fine-scale habitat quality.

A Brief Description of Avian Communities in Sungai Tongod Forest Reserve, Tongod, Sabah, Malaysia

A rapid assessment of the avifauna of Sungai Tongod Forest Reserve (STFR), a logged-over forest, was conducted in Tongod district in central Sabah, Malaysia. A modified MacKinnon List method was used to assess species diversity. The four-day survey recorded a total of 15 MacKinnon lists, with 342 individuals detected. A total of 85 species from 38 families were recorded, with H=4.07 and EH=0.70. True species richness was estimated (using SuperDuplicates® online calculator) to be approximately 114 species, with about 30 species not detected. There were 10 Bornean endemics, half of which were listed as Least Concerned, two as Near Threatened, and one as Vulnerable, in the IUCN Red List of Threatened Species. The Pellorneidae, Pycnonotidae and Nectariniidae were represented by eight, seven and six species respectively. The family Pycnonotidae had the highest number of individuals at 40 followed by Pellorneidae with 35. The five most detected species comprised 42.4 % of all individuals. The most detected species were the Bold-striped Tit-babbler (17 individuals), Green Iora (15), Pink-necked Green Pigeon (15), Black-and-yellow Broadbill (12), and Black-headed Bulbul (12). Most of the species detected (77) were forest-dependent, of which 62 were strictly forest birds. Insectivores comprised the most dominant dietary guild, i.e., 25 species (from 22 families). Frugivores ranked second with 25 species from 10 families.

Influences of fern and vine coverage on the above-ground biomass recovery in a Bornean logged-over degraded secondary forest

ABSTRACT Tropical secondary forests are widespread in the anthropogenically modified landscapes. Because tropical secondary forests were known to show a steady rate of above-ground biomass (AGB) recovery, they were expected to play a crucial role in carbon sequestration. However, in a preliminary survey of logged-over forests in Borneo, some patches covered with ferns and vines do not seem to recover steadily despite the fact that several decades have passed since the last logging. The presence and abundance of fern/vine thickets may affect the AGB recovery, but few studies have investigated the effects of the thickets. We established a total of seventeen 20-m radius circular plots in logged-over forests, Sabah, Malaysia, with a varying degree of fern/vine coverage, and tested the hypothesis that the greater fern/vine coverage would retard the AGB recovery. The net AGB accumulation rate from 2014 to 2019 was lower in the forests with a higher fern/vine coverage. Our lower bound of the accumulation rate was much lower than the previously reported rates elsewhere. The number of newly recruited and small-diameter trees was lower, and the mortality of remnant trees was higher with increasing fern/vine coverage. The growth rate of the extant pioneer trees, which are expected to significantly contribute to the initial build-up phase of the secondary succession, was inhibited when ferns and vines covered the canopy. Our study suggests that the secondary succession is arrested and the recoverability of forest stands is lower than formerly predicted when they are covered by thick ferns and vines.

Stand Structure Dynamic of Logged Over Forest after Selective Timber Harvesting in Boven Digoel, Papua

Logged-over natural forest has a different stand structure and composition from primary natural forest due to logging activities. This study aimed to examine forest dynamics (upgrowth, ingrowth, and mortality) of the logged-over forest in PT. Tunas Timber Lestari (TTL) Papua in both stands with and without treatments. The data used in this study were based on the measurement in the Permanent Measurement Plots (PUP) for ten years. This study grouped data into five diameter classes of 10 cm intervals and three wood species groups (meranti timber, mixed timber, and non-commercial timber). Data analysis was carried out by forming a stand structure model and calculating the rate of ingrowth, upgrowth, and mortality. The stand structure model for each species group in stands with treatment had a significant R² value compared to those without treatment. The average ingrowth rate in the stands with treatment was smaller than without treatment. The values of upgrowth varied with the increase in diameter classes for both stands with and without treatments. The mortality rate in stands without treatment tended to be higher, especially in mixed timber and non-commercial timber groups. In contrast, in the meranti timber group, the mortality rate mostly occurred in the stands with treatment. The stand structure models resulting in this study can be used as important information in determining appropriate silvicultural options for forest stands. Keywords: Forest dynamics, logged-over forest, meranti, selective logging

Effect of soil physical properties on soil infiltration rates

The physical properties of the soil are studied to understand the influence of soil properties on infiltration rate. The effect of soil physical properties on infiltration rates on logged-over forests was measured with a mini-disk infiltrometer across various levels of soil disturbances. Results of soil analysis suggest are mostly loamy texture and the bulk density has varied from 0.74 - 1.02 g cm−3, respectively. The basic infiltration rate has varied from a minimum of 0.61 mmhr−1 to a maximum of 45.22 mmhr−1 with an average of 3.81 mmhr−1. The results of simple regression analyses showed that there was little association between the physical properties of the soil and the infiltration rate. This study suggests that the high variation of infiltration rate in this study site is attributed to the high spatial variability of soil properties.

Mapping the Spatial Distribution of Fern Thickets and Vine-Laden Forests in the Landscape of Bornean Logged-Over Tropical Secondary Rainforests

Forest degradation has been most frequently defined as an anthropogenic reduction in biomass compared with reference biomass in extant forests. However, so-defined “degraded forests” may widely vary in terms of recoverability. A prolonged loss of recoverability, commonly described as a loss of resilience, poses a true threat to global environments. In Bornean logged-over forests, dense thickets of ferns and vines have been observed to cause arrested secondary succession, and their area may indicate the extent of slow biomass recovery. Therefore, we aimed to discriminate the fern thickets and vine-laden forests from those logged-over forests without dense ferns and vines, as well as mapping their distributions, with the aid of Landsat-8 satellite imagery and machine learning modeling. During the process, we tested whether the gray-level co-occurrence matrix (GLCM) textures of Landsat data and Sentinel-1 C-band SAR data were helpful for this classification. Our study sites were Deramakot and Tangkulap Forest Reserves—commercial production forests in Sabah, Malaysian Borneo. First, we flew drones and obtained aerial images that were used as ground truth for the supervised classification. Subsequently, a machine-learning model with a gradient-boosting decision tree was iteratively tested in order to derive the best model for the classification of the vegetation. Finally, the best model was extrapolated to the entire forest reserve and used to map three classes of vegetation (fern thickets, vine-laden forests, and logged-over forests without ferns and vines) and two non-vegetation classes (bare soil and open water). The overall classification accuracy of the best model was 86.6%; however, by combining the fern and vine classes into the same category, the accuracy was improved to 91.5%. The GLCM texture variables were especially effective at separating fern/vine vegetation from the non-degraded forest, but the SAR data showed a limited effect. Our final vegetation map showed that 30.7% of the reserves were occupied by ferns or vines, which may lead to arrested succession. Considering that our study site was once certified as a well-managed forest, the area of degraded forests with a high risk of loss of resilience is expected to be much broader in other Bornean production forests.

Assessment of reduced impact logging technique at different logging intensity

Despite increased recognition of the value provided by forests, the tropical forest potential continued to be seriously degraded, especially by overexploitation. In the field of harvesting, achieving sustainable forest management requires environmentally responsible logging, hence the growing interest in reduced impact logging (RIL) as an alternative strategy to promoting good forestry practices be expected can continue to fulfil the functions of forest ecosystems. The study was conducted in 100 ha of the first cutting cycle and 200 ha of the second cutting cycle of 22 years logged over the forest in Indonesia Borneo. The degraded level is measured based on disclosed area, while potential production of the residual stand is predicted by using growth increment data from a permanent sample plot. Harvest intensity influence significantly to residual stand condition with a positive correlation. Potential production of residual trees in the first logged-over forest after 35 years is almost recovered then can be achieved sustainable yield. It means that 22 years is not a sustainable cutting cycle. The disclosure area after the second logging was high of 66.89 to 69.36. Potential production of residual trees was very low and need 35.5 to 42.8 years to recover, however, the cutting cycle needs a longer time to achieve sustainable forest management as long as 57.3 to 63.2 years. Based on this study, regulation of reduced cutting cycle on logged-over forest after 20 years is not recommended to implement in natural forests.

Changes in tree functional composition and forest functioning ten years after logging and thinning interventions in Bornean tropical forests

Examining ecosystem functioning of logged-over forests requires a quantitative trait-based monitoring approach, in addition to a taxonomic approach, which allows for evaluation of the accompanying shifts in species traits and functional composition. Our study evaluated forest regrowth after different logging and thinning techniques applied to 60 one-hectare forest subplots in East Kalimantan that were logged using selective conventional and reduced-impact techniques. We used seven functional traits to compare the short-term (∼1-year) and longer-term (∼10-year) changes in functional diversity and composition of the forest. Both conventional and reduced impact logging resulted in higher functional diversity after 10 years, but forest functional traits shifted away from those observed in unlogged (control) subplots. Reduced-impact logging led to smaller deviations in functional composition compared to unlogged forest. We found that low-intensity reduced-impact logging, i.e., <3 m2 ha−1 (equivalent to 5 trees ha−1 or approximately 42 m3 ha−1), maintained functional diversity equivalent to unlogged forest measured in 12 one-hectare control plots. Selectively logged forest subplots with liberation thinnings increased functional diversity while leaving the trait composition unchanged. Thinned subplots exhibited higher functional diversity than the un-thinned subplots and greater similarity to unlogged forest. However, high-intensity thinning, i.e., >10 m2 ha−1, resulted in large functional traits shifts away from unlogged forest. Our study suggests that preserving the original forest functionality, i.e., by applying low intensity, reduced-impact logging and thinning operations, represents a sustainable strategy for long-term tropical forest management.

Relationships between tree-community composition and regeneration potential of Shorea trees in logged-over tropical rain forests

ABSTRACT Logged-over forests are widespread in SE Asia, and these forests vary greatly in tree-community composition ranging from a near pristine to a greatly modified forest due to repeated high-impact logging. It is a critical concern in terms of forest management and conservation whether modified forests can recover to their original states. However, greatly modified forests may lose the resilience due to the lack of next-generation seedlings. We examined the regeneration potential of Shorea, a dominant genus in pristine forests, in various forests ranging from pristine to degraded forests, and investigated the relationship between the tree-community composition in canopy layer and the regeneration potential in north Borneo. In non-metric multidimensional scaling (nMDS) analysis based on the tree-community composition at genus level, 31 study plots were sorted in the order from pristine to degraded forests along the axis-1 with decreasing the axis-1 scores, and this score was used as a metric of forest intactness. Size distribution of Shorea trees combining all congeneric species showed an inverse-J shape in most plots excluding some degraded forests. The skewness of size distribution was high in pristine forests but remarkably decreased in degraded forests. The skewness reflected the abundance of seedlings in the population of Shorea trees, and it was an important metric indicating regeneration potential. The number of seedlings also decreased abruptly with decreasing forest intactness along the nMDS axis-1. The reduction in these two metrics suggests that regeneration potential is abruptly lost when the forest intactness in terms of tree-community composition is decreasing.

Soils Carbon Stocks and Litterfall Fluxes from the Bornean Tropical Montane Forests, Sabah, Malaysia

Tropical forests play an important role in carbon storage, accumulating large amounts of carbon in their aboveground and belowground components. However, anthropogenic land-use activities have increasingly threatened tropical forests, resulting in accelerated global greenhouse gas emissions. This research aimed to estimate the carbon stocks in soil, organic layer, and litterfall in tropical montane forests under three different land uses (intact forest, logged-over forest, and plantation forest) at Long Mio, Sabah, Malaysia. Field data were collected in a total of 25 plots from which soil was randomly sampled at three depths. Litterfalls were collected monthly from November 2018 to October 2019. The results showed that the soil in the study area is Gleyic Acrisol, having pH values ranging between 4.21 and 5.71, and high soil organic matter contents. The results also showed that the total soil carbon stock, organic layer, and litterfall is higher in the intact forest (101.62 Mg C ha−1), followed by the logged-over forest (95.61 Mg C ha−1) and the plantation forest (93.30 Mg C ha−1). This study highlights the importance of conserving intact forests as a strategy to sequester carbon and climate change mitigation.

Assessment of soil carbon stocks in several peatland covers in Central Kalimantan, Indonesia

Changes in the soil carbon (C) stocks of degraded peatlands due to drainage, fire, or conversion of forest cover have not been studied much. This study aims to determine the characteristics of soil C stocks in degraded peatland covers due to logging and fire. The research was carried out on peatlands located in three villages representing peatland cover conditions in the form of primary/pristine peat swamp forest, logged-over forest, and post-fire peatland. Peat samples from each type of peatland cover were analyzed to determine the bulk density (BD) and C concentration. The results showed that peatland on the logged-over forest has the highest BD (0.135 gr cm−3) compared to the other sites. Based on the distribution of peat depth, the lowest BD was mainly found at the surface peat layers and increased significantly with the depth of peat. The C concentration with the mean value of 57.6% showed no significant differences among the three locations and at different depths. Soil C stocks in the upper one-meter depth were 621, 779, and 606 Mg ha−1 in the peat swamp forest, logged-over forest, and post-fire peatland, respectively. The total soil C stocks were ultimately determined by the peat thickness in the area.

Logging effects on seedling regeneration and diversity in a tropical moist semi-deciduous forest in Ghana

ABSTRACT The effect of time lag after logging on seedling dynamics was assessed in logged and unlogged forest plots located in the Pra-Anum Forest Reserve. Remnant tree attributes were sampled in six plots with sizes of 25 × 25 m in each forest type. Within each forest type, ten subplots with sizes 1 × 1 m were established for sampling seedling regeneration dynamics. Enumerated seedlings were grouped as pioneer, non-pioneer light demander, and shade-tolerant species. Regenerating seedlings were more diverse in the recently logged forest area characterised by Broussonetia papyrifera and Musanga cecropioides, and least in the unlogged forest driven predominantly by Celtis mildbraedii and Baphia nitida. Pioneer species were primarily dominant in the recently logged forest, while shade-tolerant and non-pioneer light-demanding species characterised the logged-over forest. Species richness and canopy openness of remnant stands explained 32 percent of the variations in regeneration richness between the logged and unlogged areas. Twenty-seven percent of the variations in seedling abundance was also explained by remnant trees richness, their size diameter and the degree to which their canopy has been opened. Logging-induced disturbance favours the sporadic emergence of pioneer species in recently disturbed areas which are later replaced by non-pioneer light-demanding or shade-tolerant species as light becomes limiting in the understory.

Is it possible that logged-over areas can recover naturally: the case of logged-over areas in South Kalimantan

Logging causes a decline in the quality of stands in all forest types. However, these forests can recover naturally. This study aims to measure the ability to recover logged-over areas based on the species composition and above-ground biomass. This research was conducted by logged-over forest in 1987, of lowland forest type in the Kintap Research Forest, South Kalimantan. The research was carried out by making a measurement plot on three types of land with the main road’s distance as a differentiating factor. Each type of measurement plot measuring 1 hectare is divided into five replications with 20 m × 100 m. The measurement parameters are the diversity of species and above-ground biomass estimated by the allometric model. The results showed that the distance difference did not affect the species composition and the potential for above-ground ground biomass. The species composition is indicated by the diversity index, evenness index, and dominance index, including above-ground biomass. Overall, more than 100 tree species present after felling and an evenness index of higher than 0.75, indicating that the community is stable with high species diversity and low dominance. This indicates that logged-over areas can recover but that recovery requires adequate regeneration after logging. The implication is that logging must leave enough standing stands. This condition will encourage natural regeneration or succession in logged-over forests.

Estimation of liana infestation above canopy in Bukit Bakar recreational park, Kelantan using an unmanned aerial vehicle

A study on lianas estimation has been conducted in 1 ha plot at Bukit Bakar Recreational Park, Machang, Kelantan. Liana infestation on tree crowns was assessed from above by using an unmanned aerial vehicle (UAV), DJI Phantom-4 Pro which was manually piloted. Liana load carried by trees were determined by calculating the percentage liana cover (%LC) and measuring crown occupancy index (COI). Collection of image data by UAV had been captured and geo-tagged with GPS location. The value of crown occupancy index (COI) depends on the accuracy of the percentage liana cover (%LC). Fourteen host trees infested by lianas were identified. The value COI of 14 lianas-infested trees were in the range between 0 – 2, indicating low and moderate infestation. One point was recorded with very low liana load, nine points with moderate liana and four points with low liana load on tree crowns with 0.76% to 29.9% of liana cover respectively. The moderate and lower values obtained was probably due to the lesser of anthropogenic disturbance and natural disturbance that occurred after 40 years of selective management system logging. The liana infestation was distributed homogeneously. The lower liana COI obtained, indicates the ongoing progress of forest succession in Bukit Bakar that gradually hindered liana proliferation within the proximity. This method could promote the local authority in forestry management particularly in managing the tree crown occupancy of liana in the logged-over forest.

Two New Distributional Records of Gliding Squirrels in Merapoh Forest Complex, Pahang

A preliminary survey on the diversity of gliding squirrels was conducted from September 2019 until February 2020 in several locations within Merapoh, Pahang, Peninsular Malaysia using standard line transect method. The survey areas include a pristine forest, logged-over forest and agro-forested plantations. Gliding squirrels were spotted using a headlamp, binoculars (8x30 magnification) and a Digital SLR affixed with a telephoto lens (Nikon D500 + Nikkor 200-500 F5.6 VR) as they are mainly nocturnal. The highlight of this short survey was two new distributional records of flying squirrels for Merapoh Forest Complex. These two species were Spotted giant gliding squirrel (Petaurista elegans) and Temminck’s gliding squirrel (Petinomys setosus). Other gliding squirrels recorded in this survey include the Red Giant gliding squirrel (Petaurista petaurista), Horsfield’s gliding squirrel (Iomys horsfieldii) and Red-cheeked gliding squirrel (Hylopetes spadiceus). Apart from gliding squirrel, a total of eleven (11) species of other squirrels were also recorded within this survey. Continuous and systematic diversity surveys on gliding squirrels are needed as it is still understudied in Malaysia especially Merapoh.

Towards better estimates of carbon stocks in Borneo's logged-over Dipterocarp forests

Tropical forests are a major reservoir of biodiversity and carbon (C), playing a pivotal role in global ecosystem function and climate regulation. However, most tropical forests, especially Borneo's forests in Southeast Asia, are under intense pressure and threatened by human activities such as logging, mining, agriculture and conversion to industrial plantations. Selective logging is known to reduce both above- and below-ground biomass by removing selected large trees, while increasing deadwood stocks through collateral logging damage and creating large gaps in the canopy. The extent of incidental damage, canopy opening and the rate of C recovery were shown to be primarily related to logging intensity. This thesis assesses the long-term effects of logging intensity on five main C pools in Dipterocarp forests in northern Borneo (Malinau District, North Kalimantan) along a logging intensity gradient ranging from 0 to 57% of initial biomass removed in 1999/2000. Our results showed that total C stocks 16 years after logging ranged from 218-554 Mg C/ha with an average of 314 Mg C/ha. A difference of 95 Mg C/ha was found between low logging intensity (&lt; 2.1% of initial biomass lost) and high logging intensity (&gt; 19%). Most C (approx. 77%) was found in living trees, followed by soil (15%), deadwood (6%) and a small fraction in litter (1%). The imprint of logging intensity was still detectable 16 years after logging. Logging intensity was thus shown to be the main driver explaining the reduction of AGC&gt;20, BGC&gt;20, in deadwood and total C stocks and an increase in deadwood. Our results quantify the long-term effects of logging on forest C stocks, especially in AGC and deadwood. High logging intensity (50% reduction of initial biomass) reduced total C stocks by 27%. AGC recovery was lower in high logging intensity plots, suggesting lowered forest resilience to logging. Our study showed that keeping logging intensity below 20% of the initial biomass can limit the long-term effects of logging on AGC and deadwood stocks.