Logging Damage Research Articles

LoggingLab: An R package to simulate reduced-impact selective logging in tropical forests using forest inventory data

Even where Reduced-Impact Logging (RIL) practices are applied, selective logging causes substantial damage to tropical forests. To further reduce selective logging damage, the practices that cause the most damage need to be identified and alternatives tested. To this end, we developed the R package LoggingLab, a spatially-explicit and individual tree-based selective logging simulator and demonstrated its functions using data from French Guiana. LoggingLab explicitly simulates damage during each stage of the selective logging process taking into account topography and hydrography, which are main constraints on logging. Most LoggingLab parameters can be easily adjusted to a wide range of local contexts. LoggingLab can also be coupled with forest dynamics models to simulate the long- term effects of different selective logging scenarios.

A service to help insurers understand the financial impacts of changing flood risk in Europe, based on PESETA IV

The European Union PESETA IV project has produced a comprehensive dataset that quantifies the impact of climate change on river flooding and damage in Europe. This data potentially has significant application in the insurance industry, but requires some steps of post-processing, and appropriate delivery mechanisms, before it can be used in practice. The post-processing approach we apply involves statistical modelling of the simulated changes in damage to estimate rates of change of log damage versus global mean surface temperature (GMST). Under linear assumptions, these rates of change can be used to calculate the change in damage between any two time-periods for any GMST scenario. Under further assumptions, these changes can be used to adjust many of the metrics of flood risk used in the insurance industry, such as average annual losses, exceedance probabilities and year loss tables. We deliver these results in two ways to suit different users in the insurance industry. First, the rates of change, and related correlations, are provided as freely available datasets for insurers who prefer to process and apply the data themselves. Second, commercial online software is provided that performs some steps of the processing and application. Many sources of uncertainty affect our results. The results must not therefore be interpreted too literally, but hopefully give a good indication of the sign and rough magnitude of the likely changes in river flood damage due to climate change. Future studies will hopefully reduce the uncertainty.

Prospective carbon balance of the wood sector in a tropical forest territory using a temporally-explicit model

Selective logging in tropical forests is often perceived as a source of forest degradation and carbon emissions. Improved practices, such as reduced-impact logging (RIL), and alternative timber production strategies (e.g. plantations) can drastically change the overall carbon impact of the wood production sector. Assessing the carbon balance of timber production is crucial but highly dependent on methodological approaches, especially regarding system boundaries and temporality. We developed a temporally-explicit and territory scale model of carbon balance calibrated with long-term local data using Bayesian inference. The model accounts for carbon fluxes from selective logging in natural forest, timber plantation, first transformation and avoided emissions through energy substitution. We used it to compare prospective scenarios of development for the wood sector in French Guiana. Results show that intensification of practices, through increased logging intensity conducted with RIL and establishment of timber plantations, are promising development strategies to reduce the carbon emissions of the French-Guianese wood sector, as well as the area needed for wood production and hence the pressure on natural forests. By reducing logging damage by nearly 50%, RIL allows increasing logging intensity in natural forest from 20 m3 ha−1 to 30 m3 ha−1 without affecting the carbon balance. The use of logging byproducts as fuelwood also improved the carbon balance of selective logging, when substituted to fossil fuel. Allocating less than 30000 ha to plantation would allow producing 200000 m3 of timber annually, while the same production in natural forest would imply logging more than 400000 ha over 60 years. Timber plantation should be preferentially established on non-forested lands, as converting natural forests to plantation leads to high carbon emission peak over the first three decades.We recommend a mixed-strategy combining selective logging in natural forests and plantations as a way to improve long-term carbon balance while reducing short-term emissions. This strategy can reduce the pressure on natural forests while mitigating the risks of changing practices and allowing a diversified source of timber for a diversity of uses. It requires adaptation of the wood sector and development of technical guidelines. Research and monitoring efforts are also needed to assess the impacts of changing practices on other ecosystem services, especially biodiversity conservation.

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 (< 2.1% of initial biomass lost) and high logging intensity (> 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>20, BGC>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.

Combined membrane filtration and 265 nm UV irradiation for effective removal of cell free antibiotic resistance genes from feed water and concentrate

The removal of cell free DNA (plasmids) carrying antibiotic resistance genes (ARGs) was investigated at bench-scale using ultrafiltration (UF), nanofiltration (NF) and reverse osmosis (RO) membranes commonly applied in water reuse applications. The removal of the plasmid spiked to ultrapure water was determined using a direct qPCR method. More than 99% plasmid removal was achieved by membranes with 1 kDa molecular weight cut off (MWCO). Membranes with lower MWCO showed complete removal under the specific experimental conditions, reaching a maximum log reduction value above 6.6. The concentrate from membrane filtration was further subjected to UV-LED irradiation at 265 nm. The required fluence for 1 log damage was 73 mJ/cm2 for the 267 target bp segment and 23 mJ/cm2 for the 601 target bp segment, respectively. With these two DNA segments, the inactivation rate per segment length was higher for the larger segment, in accordance with a higher pyrimidine and TT content, compared with the smaller fragment. Target DNA was not detectable anymore when using 100 and 300 mJ/cm2 for the 601 and 267 bp segments respectively. The results indicate that membrane filtration, combined with UV-LED treatment of the concentrate, can be an effective measure to remove and inactivate ARGs from water to prevent their release to the environment.

Carbon recovery following selective logging in tropical rainforests in Kalimantan, Indonesia

BackgroundThe knowledge gap regarding post-logging carbon recovery by increased growth is becoming more crucial to understand the significant contribution of forest to climate change mitigation. We assessed the ability of tropical forests in Indonesia to recover carbon following conventional logging. We evaluated carbon re-growth of 10,415 trees in permanent sample plots (PSPs) in East Kalimantan. Four different post-harvesting silvicultural treatments including liberation, refining, thinning, and control were applied in the PSPs. We estimated the carbon recovery period using three different scenarios of total carbon losses due to logging. In the first scenario, we used an existing factor of logging damage and increased it for assuming the range of carbon losses due to different logging practices.ResultsUnder the existing conventional logging practice, the concession annually emits 51.18 tC∙ha− 1, of which 16.8% are extracted from the forest as raw timber, 38% are logging losses, and 45.2% are emissions due to infrastructure development for logging operation. Increasing the logging damage factor two and three times led to an increase in carbon emission to 70.76 and 90.34 tC∙ha− 1, respectively. The recovery time of the aboveground carbon is 26 years in Scenario 1, 36 years in Scenario 2, and 46 years in Scenario 3. We found no significant effect of the silvicultural treatment type on carbon recovery, but significant effect of the sites was observed.ConclusionsWe found that the time taken to restore the carbon to the level found in undisturbed forests is considerably longer than the current intervention cycles. The time needed to recover biomass and carbon-stock noticeably depends on the intensity of logging interventions, demonstrating the benefits of using improved harvesting e.g., reduced impact logging to reduce emissions. The study found that site variability has a significant effect on the carbon recovery time. Different silvicultural treatments, on the other hand, have no effect on the recovery time. The study suggests that it is not appropriate to establish an intervention cycle based on arbitrary choice; the time between interventions must be based on logging losses and site specific growth potential to ensure sustainable management of forests.

Long-Term Impacts of Selective Logging on Amazon Forest Dynamics from Multi-Temporal Airborne LiDAR

Forest degradation is common in tropical landscapes, but estimates of the extent and duration of degradation impacts are highly uncertain. In particular, selective logging is a form of forest degradation that alters canopy structure and function, with persistent ecological impacts following forest harvest. In this study, we employed airborne laser scanning in 2012 and 2014 to estimate three-dimensional changes in the forest canopy and understory structure and aboveground biomass following reduced-impact selective logging in a site in Eastern Amazon. Also, we developed a binary classification model to distinguish intact versus logged forests. We found that canopy gap frequency was significantly higher in logged versus intact forests even after 8 years (the time span of our study). In contrast, the understory of logged areas could not be distinguished from the understory of intact forests after 6–7 years of logging activities. Measuring new gap formation between LiDAR acquisitions in 2012 and 2014, we showed rates 2 to 7 times higher in logged areas compared to intact forests. New gaps were spatially clumped with 76 to 89% of new gaps within 5 m of prior logging damage. The biomass dynamics in areas logged between the two LiDAR acquisitions was clearly detected with an average estimated loss of −4.14 ± 0.76 MgC ha−1 y−1. In areas recovering from logging prior to the first acquisition, we estimated biomass gains close to zero. Together, our findings unravel the magnitude and duration of delayed impacts of selective logging in forest structural attributes, confirm the high potential of airborne LiDAR multitemporal data to characterize forest degradation in the tropics, and present a novel approach to forest classification using LiDAR data.

A comprehensive synthesis of liana removal experiments in tropical forests

AbstractLianas are a quintessential feature of tropical forests and are often perceived as being poorly studied. However, liana removal studies may be one of the most common experimental manipulations in tropical forest ecology. In this review, we synthesize data from 64 tropical liana removal experiments conducted over the past 90 yr. We explore the direction and magnitude of the effects of lianas on tree establishment, growth, survival, reproduction, biomass accretion, and plant and animal diversity in ecological and forestry studies. We discuss the geographical biases of liana removal studies and compare the various methods used to manipulate lianas. Overall, we found that lianas have a clear negative effect on trees, and trees benefitted from removing lianas in nearly every study across all forest types. Liana cutting significantly increased light and water availability, and trees responded with vastly greater reproduction, growth, survival, and biomass accumulation compared to controls where lianas were present. Removing lianas during logging significantly reduced damage of future merchantable trees and improved timber production. Our review demonstrates that lianas have an unequivocally detrimental effect on every metric of tree performance measured, regardless of forest type, forest age, or geographic location. However, lianas also appear to have a positive contribution to overall forest plant diversity and to different animal groups. Therefore, managing lianas reduces logging damage and improves timber production; however, the removal lianas may also have a negative effect on the faunal community, which could ultimately harm the plant community.

Corsican Pine (Pinus laricio Poiret) Stand Management: Medium and Long Lasting Effects of Thinning on Biomass Growth

With the aim of acquiring better comprehension of the ecological and productive aspects of the management of pine forests, we monitored logging damage and evaluated the effects of thinning on stand growth 20 years after the treatment in a Pinus laricio Poiret stand in central Italy. The objectives of the present study were to estimate the injury levels to the remaining trees after thinning; to assess logging damage in the long-term by monitoring residual trees at the end of thinning; to evaluate the effect of damage on the radial growth of trees; to assess the stand dynamics in relation to injury levels and the treatment applied in a twenty-year range; to understand a possible treatment return time; and to evaluate the existence of the “thinning shock”. The results were that 20 years after treatment, the stand dynamics showed a complete recovery; logging damage did not affect the radial growth of P. laricio over time; a second treatment seem to be sustainable starting from the fifteenth year after the previous treatment; and the thinning shock can be clearly evaluated in the first six to seven years after the treatment.

Automated method for measuring the extent of selective logging damage with airborne LiDAR data

Selective logging has an impact on the global carbon cycle, as well as on the forest micro-climate, and longer-term changes in erosion, soil and nutrient cycling, and fire susceptibility. Our ability to quantify these impacts is dependent on methods and tools that accurately identify the extent and features of logging activity. LiDAR-based measurements of these features offers significant promise. Here, we present a set of algorithms for automated detection and mapping of critical features associated with logging – roads/decks, skid trails, and gaps – using commercial airborne LiDAR data as input. The automated algorithm was applied to commercial LiDAR data collected over two logging concessions in Kalimantan, Indonesia in 2014. The algorithm results were compared to measurements of the logging features collected in the field soon after logging was complete. The automated algorithm-mapped road/deck and skid trail features match closely with features measured in the field, with agreement levels ranging from 69% to 99% when adjusting for GPS location error. The algorithm performed most poorly with gaps, which, by their nature, are variable due to the unpredictable impact of tree fall versus the linear and regular features directly created by mechanical means. Overall, the automated algorithm performs well and offers significant promise as a generalizable tool useful to efficiently and accurately capture the effects of selective logging, including the potential to distinguish reduced impact logging from conventional logging.

Using a tree-based approach to evaluate logging damage in a tropical mixed deciduous forest of Myanmar: comparison with cases in Cambodia

ABSTRACTLogging damage to residual trees is an important parameter when considering the sustainability of selective logging in tropical natural forests. Here, we applied a proposed tree-based approach to evaluate logging damage in a tropical mixed deciduous forest in Bago Yoma, Myanmar and compared the cases with semi-evergreen forests of Cambodia. The logging damage was assessed in twenty 0.1-ha plots, each of which contained the stump and crown of one felled tree, and multinomial logistic regression was used to quantify the probability of the felled tree causing severe, slight, or no damage to residual trees. In both cases of Myanmar and Cambodia, severe damage was dependent on the size of the residual and felled trees, while slight damage was independent of the size of felled trees. There was no slight damage of residual trees with ≥50 cm diameter at breast height (DBH) in Myanmar, whereas slight damage increased with residual tree size in Cambodia and in tropical rain forests of other countries. This difference could be attributed to the sparseness of standing trees (98 trees ha−1) in our study site in Myanmar, which made it easier to control the felling direction to avoid damage to larger residual trees. Additionally, the probability of increasingly severe damage with increasing DBH of the felled trees was higher in Myanmar than in Cambodia; one of the reasons may be the steeper terrain at the Myanmar site.

Economic Analysis of Residual Tree Damage Following Selective Logging in a Caspian Hardwood Forest

This study evaluated the logging damage to residual trees following logging operations by opportunity and replacement cost approaches. A total density of 5.1 trees/ha and 17.3m3/ha of wood were harvested. On average, 9.8 trees were damaged for every tree extracted including 8 trees killed or severely damaged. The results of showed that selective cutting can damage residual trees US$47369.25. The results of this study also suggest that logging practices need to be accompanied by close supervision of field personnel and post logging site inspections to be implemented properly.

A methodological framework to assess the carbon balance of tropical managed forests.

BackgroundManaged forests are a major component of tropical landscapes. Production forests as designated by national forest services cover up to 400 million ha, i.e. half of the forested area in the humid tropics. Forest management thus plays a major role in the global carbon budget, but with a lack of unified method to estimate carbon fluxes from tropical managed forests. In this study we propose a new time- and spatially-explicit methodology to estimate the above-ground carbon budget of selective logging at regional scale.ResultsThe yearly balance of a logging unit, i.e. the elementary management unit of a forest estate, is modelled by aggregating three sub-models encompassing (i) emissions from extracted wood, (ii) emissions from logging damage and deforested areas and (iii) carbon storage from post-logging recovery. Models are parametrised and uncertainties are propagated through a MCMC algorithm. As a case study, we used 38 years of National Forest Inventories in French Guiana, northeastern Amazonia, to estimate the above-ground carbon balance (i.e. the net carbon exchange with the atmosphere) of selectively logged forests. Over this period, the net carbon balance of selective logging in the French Guianan Permanent Forest Estate is estimated to be comprised between 0.12 and 1.33 Tg C, with a median value of 0.64 Tg C. Uncertainties over the model could be diminished by improving the accuracy of both logging damage and large woody necromass decay submodels.ConclusionsWe propose an innovating carbon accounting framework relying upon basic logging statistics. This flexible tool allows carbon budget of tropical managed forests to be estimated in a wide range of tropical regions.

Effect of logging wounds on diameter growth of beech (Fagus orientalis Lipsky) trees following selection cutting in Caspian forests of Iran

Logging damage to residual trees during selection cutting may lead to serious economic losses in terms of both timber quality and diameter growth reduction. In this study, we investigated the effect of logging operations on residual tree damage and the consequence of injuries on diameter growth in an uneven-aged mixed forest dominated by beech (Fagus orientalis Lipsky). The diameter growth of 56 wounded and 56 unwounded beech trees were compared 12 years after selected logging of other trees had taken place in an Iranian Caspian forest. Of total logging wounds, 25.0 % (14 wounds) were caused by felling operations and 75.0 % (42 wounds) were caused by winching operations. The reduction in diameter growth of wounded beech trees was only observed in the breast height DBH range below 55 cm. The diameter growth of wounded trees was 8.1 % lower than in unwounded trees. The vertical distance from the ground of wounding was a significant factor in diameter growth. Wounds that were larger than 200 cm2 in area significantly reduced diameter growth of beech trees. Whether wounds were closed or open wounds had no significant effect on diameter growth but decayed wounds reduced diameter growth by 15.3 %. This study suggested that intensive logging wounds reduce diameter growth, especially in young beech trees. In addition to the intensity, size and position of wounds and tree age, the reduction of diameter growth was related to the ratio of wound size to stem area.

Tree-based approach to evaluate size dependence of residual tree damage caused by selective logging: Case study in tropical semi-evergreen forests of Cambodia

Logging damage to residual trees is one of the fundamental components in evaluating the sustainability of tropical selective logging in terms of timber production, carbon retention and biodiversity conservation. Although many studies have taken an area-based approach to tropical rain forests, we adopted a tree-based approach to quantify the dependence of residual tree damage on the size of residual and felled trees. We used data from 179 plots, each 25m×40m, covering the stump and crown of one felled tree in Cambodian tropical semi-evergreen forests. We used the mixed-effects multinomial logistic regression model to predict the probability of a residual tree sustaining severe, slight or no damage. Increasing size of residual trees decreased the probability of severe damage and increased that of slight damage. The probability of total damage (severe plus slight) was nearly constant, regardless of the size of residual trees. Increasing size of the felled tree caused greater probability of severe damage, but did not influence the probability of slight damage. Interestingly, our prediction of total damage rate from the tree-based modeling approach of the Cambodian semi-evergreen forests is very consistent with the findings of previous studies using the area-based approach in Indonesia. The departure of our study results from those of other studies may be explained by differences in felled tree size and terrain slope. The inclusion of tree-size dependence in logging damage estimation would increase its accuracy and comparability across different types of tropical forests.

A Comparative Study of Carbon Stock Changes from Different Logging Techniques in Ulu Jelai Forest Reserve, Kuala Lipis, Pahang


 
 
 Conventional logging practices are often highly destructive to forest ecosystems. Heavy machinery can compact the soil and destroy vegetation. Previous research by others have demonstrated that environmental damage can be minimized through the use of site- sensitive harvesting techniques. Forest harvesting in the inland forest in Malaysia is generally carried out by a combination of crawler tractor and winch lorry, which we defined as the current logging technique. Under the current logging technique, crawler tractors are used to skid logs from felling sites to skid trails and winch lorries continue the transportation to the roadside landings. In the early nineties, a Low Impact Logging (LIL) practice using an improved logging system was carried out in some forest areas in Peninsular Malaysia. The technology, called logfisher was mainly deployed to retrieve logs from rocky and deep, narrow ravine which was deemed uneconomical, difficult and dangerous for the crawler tractor to operate. In certain logging areas in Pahang, a combination of crawler tractor and logfisher is being used which we defined in this study as LIL. The study focuses on quantifying the carbon stock changes from the different logging techniques in Lipis, Pahang. Based on preliminary results, the LIL technique showed less carbon loss if the carbon stocks before and after logging were compared. This study indicates that different logging techniques results in different impact on the total residual forest carbon stocks. The introduction of LIL systems and practices have indeed reduced the logging damage and improved stand conditions. Improvement to the current practice, enhance the productivity of the residual stand and reduce forest degradation in terms of carbon stocks as well as other ecological co-benefits.
 
 

Strategies for Achieving Sustainable Logging Rate in the Brazilian Amazon Forest

Data of increment of the remnant trees after logging, ingrowth and mortality was obtained by assessment before logging and after 6 years, two sites of 50 ha, in Amazon forest. Logging scenarios were simulated to identify the logging rate potential for each studying site, by diameter class projection method. The cycle of 35 years and the logging rate of 30 m3.ha-1 exceed the time required for recovery in the primary forest, in the studied site. The simulation showed that in the studying area, a well-planned logging, with minimum logging damage would be possible to implement an initial cycle of 25 years to the forest to recover 30 m3.ha-1, if 50% of the timber stock were reserved. The forest increment, beyond important factors such as the increase of individual species, is quite dependent on the remnant trees.

Felling and skidding damage to residual trees following selection cutting in Caspian forests of Iran

The felling and skidding damage to residual trees was investigated in a selectively cutting operation in the Caspian forest of Iran. The logging operation was performed by chainsaw and cable skidder. Prelogging, after felling and skidding operations residual tree injuries (species, DBH and damage) were inventoried by systematic plot sampling. Two types of tree damage were observed: destroyed and injured. In this study felling operations mainly injured trees whereas skidding was the main cause of destruction. The percentage of destroyed and injured residual trees by felling operations was 1.4% and 3.4%, whereas the percentage of destroyed and injured residual trees by skid­ding operations was 5.2% and 11.1%. About 87% of destroyed trees were found in the DBH class smaller than 22.5 cm. Maple and Alder were the most damaged trees among the other trees species. Damage to the lower bole and wood damaged intensity were the most common type of injury. To reduce the stand damage, skid trails should be planned before felling and felling directions should be predetermined. In the selection cutting management, limiting logging damage to residual trees must therefore remain a major objective.    

Optimized Floating Refugia: a new strategy for species conservation in production forest landscapes

Timber production forests can support diverse ecological communities, but existing conservation strategies fail to maximize this potential. While methods for limiting logging damage and locating biological reserves have been developed, strategies focused on the sequence and arrangement of harvest units are lacking, particularly for situations in which species-specific knowledge is limited. We present a new landscape-level approach to forest conservation that anticipates local extinctions and focuses on facilitating re-colonization via strategic spatiotemporal harvest plans (which are informed by species occurrence data only). As a proof of concept, we applied our framework to data from four tropical forest sites and found clear benefits of optimized spatiotemporal harvest plans relative to non-optimized harvest plans (random and three pattern-based plans). Our proposed approach, termed the Optimized Floating Refugia strategy, requires minimal species-specific knowledge and can be used to enhance existing conservation efforts (e.g. biological reserve establishment, reduced-impact logging). The approach effectively prioritizes logging-sensitive habitat specialists with restricted ranges and thus provides the largest benefits to the most extinction-prone species. This simple but novel method shows promise as a general strategy to improve biodiversity conservation in species-rich production forest landscapes.

Economic analysis on log damage during logging operation in Caspian Forests

Waste wood was studied in an economic enterprise by logging, function, tree species and log size in four Caspian hardwood sites. Damaged logs were recorded with additional information obtained for the location, dimensions and type of damage. The data were analyzed statistically to determine significant differences of damage during logging process. The results indicated that animal harvesting systems cause more volume (40.5% of log volume) and value loss (89.5 $·m−3) to logs than mechanized harvesting systems (13.9% and 6.0 $·m−3), also bucking resulted in significantly more volume (9.9% of log volume) and value loss (5.5 $·m−3) when compared to skidding (0.2% of log volume and 0.2 $·m−3), decking (0.4% of log volume and 0.2 $·m−3) and loading (0.2% of log’s volume and 0.3 $·m−3) operations. Study showed that the processes of skidding, decking and loading of logs have very little impact on damage levels. Volume and value losses of damaged logs are not sensitive to tree species and log size. The information from the field study is important in creating new guidelines or training to help minimize hardwood log damage during the timber harvesting process.