Regeneration Of Commercial Tree Species Research Articles

Short Communication: Effect of skid trails on the regeneration of commercial tree species at Balah Forest Reserve, Kelantan, Malaysia

Razali N, Ismail MH, Kamarudin N, Zaki PH. 2014. Effect of skid trails on the regeneration of commercial tree species at Balah Forest Reserve, Kelantan, Malaysia. Biodiversitas 15:240-244. Skidding operation has been reported as one of the factor to forest soildegradation and vegetation disturbance. Assessing tree regeneration by the effect of the skid trail from harvest operation is important todetermine the recovery rate of the forest stand. A study was conducted to accomplish the following objectives, (i) to measure the treeregeneration rates at different distance from skid trails, and (ii) to evaluate the dominance and species diversity of regenerated trees. Atotal of five plots with size of 50 m by 2 m were established in two skid trails of natural forest that has been logged in 2012. Each plotcontains five sub-plots of 2 m by 2 m in different locations namely skid track, edge and forest. The number of seedlings and saplings,species richness and diversity, and dominance regeneration were analyzed. Results showed that the number of species regeneration wasnot significantly different in both skid trails. For skid trail 1 the number of seedling and saplings was highest on skid trail tracks (meanspecies diversity = 0.45). Meanwhile skid trail 2 showed the greatest species regeneration at edges (mean species diversity =0.65).Frequency value for Elateriospermum tapos was high due to the existence of mother tree in the area that provides a great number ofseedlings. The dominance regeneration in both skid trails originated from non-dipterocarp families. There were 42 non-dipterocarp seedling and saplings in skid trail 1, and 182 in skid trail 2. While only 2 dipterocarp seedling and saplings in skid trail 1, and 8 in skid trail 2. Enrichment planting is suggested as dipterocarp species have low growth rate compared to the non dipterocarp species.

Disturbance Level Determines the Regeneration of Commercial Tree Species in the Eastern Amazon

AbstractThe effects of reduced‐impact logging (RIL) on the regeneration of commercial tree species were investigated, as long‐term timber yields depend partly on the availability of seedlings in a managed forest. On four occasions during a 20‐month period in the Tapajós National Forest (Eastern Amazon, Brazil), seven commercial tree species were assessed as follows: the long‐lived pioneers Bagassa guianensis and Jacaranda copaia; the partially shade‐tolerant Hymenaea courbaril, Dipteryx odorata, and Carapa guianensis; and the totally shade‐tolerant Symphonia globulifera and Manilkara huberi. In 2439 10 × 10 m plots, all individuals < 20 cm diameter at breast height (dbh) were assessed over three intervals, before, during, and after the forest being logged. Before logging, the density of seedlings and saplings of the seven species did not change. Logged trees were spatially aggregated, with 9.2 percent of the plots being heavily impacted by logging. After logging, the recruitment rate increased more than the mortality rate, so that post‐harvesting densities of seedlings and saplings increased. The increase in density was concentrated in logged plots with more disturbances. It is concluded that post‐harvesting heterogeneity of micro‐environments created by RIL may be an important component to be taken into account for sustainable forest management and conservation of commercial species.

Regeneration of Commercial Tree Species and Long Term Compositional and Structural Changes in a Logged and Silviculturally Treated Brazilian Rainforest, 1955–1993

The study presented here consisted of an extensive literature investigation on the long term silvicultural experiments of Curua Una research station in the state of Para, Brazil. The objective of the work was to assess the long term ecological and financial sustainability of a set of silvicultural treatments by using numerical figures derived from the literature related to the financial and ecological impacts of the different treatments in the scale of calendar decades. There were 5 treatments including undisturbed forest (control). The remaining four where in two categories. The first included measures to increase natural regeneration of commercial species prior to exploitation. The second included measures aimed at increasing stocking of commercials after exploitation. Adequate data was found to assess the short term success rate of all 5 treatments in terms of achieving adequate stocking of commercial tree species in sizes of trees ≤5 cm dbh in the first few years after initiation. It was also possible to assess tree species community composition, structure and timber financial value for trees ≥5 cm dbh for a period of 15 years following initial treatment for one and for 36 years after initial treatment for two others. The measures used where the stocking index (S.I.) and the establishment factor (E.F.) for the early results and the Shannon-Weinner species diversity index, total % volume of commercial tree species (TPCTV), total volume of potentially commercial tree species (TPTV), harvestable volume in the year 1993 (HV), number of stems ha−1 (STD) and stand basal area in m2 ha−1. Results showed that overall silvicultural systems that included post exploitation treatments where generally more sustainable in terms of long term biodiversity value and more financially profitable relative to systems which relied on post exploitation treatments. These results suggest that drastic revision of current legislation must take place in nations with Amazonian forest because these currently include only post exploitation silvicultural treatments.

Regeneration of commercial tree species in a logged forest in the Selva Maya, Mexico

One of the main threats to the sustainability of community forestry in the Selva Maya is insufficient regeneration of commercial tree species. We evaluated the regeneration status of 22 commercial tree species in a managed semideciduous tropical rain forest in Southern Mexico. The study was carried out in six harvesting areas along a 16-year chronosequence. In each area, 10 transects (1000 m 2) were established and all trees >50 cm height and <10 cm diameter were recorded. We evaluated the relationships between seedling and sapling abundance, and canopy cover and disturbance condition (closed forest, canopy gap, log landing, skid road, primary road and secondary road). The area occupied by closed forest canopy increased with age of harvesting area (65–91% of sampled area), while the area occupied by canopy gaps decreased (22–9%). Log landings occupied less than 1% of the sampled area. The predominant canopy cover was 75–80% in all harvesting areas, even in the most recently harvested areas. The highest densities of seedlings and saplings, of both shade tolerant and intolerant species, were found in log landing and skid trails, followed by secondary roads. Even Simarouba glauca, a shade tolerant species, displayed higher densities in sites with ≤65% of canopy cover. Our results support previous findings and indicate that the levels of disturbance caused by existing harvesting procedures may be inadequate to promote sufficient regeneration of not only light demanding desirable species but also for some of the evaluated shade tolerant species of commercial interest. Seedling and sapling densities exhibited by Swietenia macrophylla, for example, are insufficient to support current harvesting rates. The application of a spatial mixed system with patch-cuts of different sizes, a consequence of group felling, could be applied to provide the necessary conditions for the regeneration of the main commercial species.

Regeneration of commercial tree species following silvicultural treatments in a moist tropical forest

Silvicultural treatments are generally performed to improve yields of commercially valuable tree species by increasing their recruitment and growth rates. In this study we analyze the effects of three different sets of silvicultural treatments on the densities and growth rates of seedlings, saplings and poles of 23 commercial tree species in a moist tropical forest in Bolivia. The treatments vary in intensity of logging and silviculture application, and are compared to a control treatment. Silvicultural treatments applied were liberation of future crop trees from lianas and neighboring competing trees, soil scarification and stand refinements. Treatments were applied to twelve 27-ha plots. In each plot 4 transects were established to assess the density and growth of the regeneration of the 23 commercial species. Effects were measured 1 and 4 years after treatment application and were described using three ecological guilds; shade-tolerant species, partially shade-tolerant species, and long-lived pioneers. We found that the intensive silviculture treatment had the largest impact on the density and growth rates of the regeneration of the commercial species. Overall, the density of regeneration of the commercial species was higher in the control treatment than in the logged treatments 1 year after treatment application, but 3 years later these differences had disappeared. Nevertheless, there were marked shifts in densities when different size classes were considered. In nearly all treatments, the number seedlings decreased over time, while the number of saplings and poles increased. Overall shade-tolerant species were more abundant than the other two ecological guilds. Treatment had a positive effect on density only for long-lived pioneers. Growth of commercial tree regeneration was strongly affected by treatment and was highest in the intensive silvicultural treatment plots where growth of long-lived pioneers was twice that of shade-tolerant species and partial shade-tolerant species. Apart from silvicultural treatments and ecological guild, light availability had the strongest effect on growth rates. These results show that different silvicultural treatments have different effects on the regeneration of commercial tree species and that ecological guilds-specific treatments should be considered in management plans for sustainable timber production in tropical lowland forests.

Regeneration of timber species following selective logging in a moist semi-deciduous forest in Ghana

The natural regeneration and growth of timber tree species were studied in four logging gaps; loading bays, tree-fall gaps, primary skid trails and secondary skid trails with forest shade as control in a moist semi-deciduous forest in Ghana. There was prolific tree seedling emergence in all the sites in the first few months following logging but declined after 8 months. Species diversity as well as seedling numbers increased with reducing gap size from the loading bays to secondary skid trails. Weed biomass, however, increased with increasing gap size. Pioneer species were relatively abundant in loading bays than all the ecological species guilds while the non-pioneers showed preference for smaller gaps. Ceiba pentandra (pioneer), for example, was the only species that survived in the loading bays for the 27-month period of the study but could not survive in the forest shade. The limited regeneration of commercial tree species and increased colonization by competing weeds in larger gaps indicate the need for better control over harvest operations through gap size reduction and post-harvest competition control treatments to ensure sustainable production of economic tree species. Keywords: Ghana, moist semi-deciduous forest, logging, regeneration Ghana Journal of Forestry Vol. 17 & 18 2005: pp. 20-35

Vegetation structure, phenology, and regeneration in the natural and anthropogenic tree-fall gaps of a reduced-impact logged subtropical Bolivian forest

Reduced-impact logging is a type of selective logging that incorporates a variety of techniques aimed at lowering levels of damage to the residual stand. In a Bolivian subtropical humid forest we studied differences in gap size, vegetation structure, regeneration and phenology between anthropogenic and natural gaps in a reduced-impact logged and unlogged forest. Harvesting took place between 1 and 4 years previously. Logging gaps were significantly larger than natural gaps (d.f. 1, variance ratio (vr.) 6.38, p = 0.014) and had significantly lower coverage of lianas (d.f. 1, vr. 8.64, p < 0.01). Seedlings were more prevalent in logging gaps than in natural tree-fall gaps (d.f. 1, vr. 13.97, p < 0.001), as were members of the herbaceous genus Heliconia (d.f. 4, vr. 3.05, p = 0.023). In larger gaps microclimatic conditions favour the regeneration of non-commercial pioneer species. We propose that ground disturbance during bole removal causes higher rates of mortality to shade-tolerant species in advanced stages of regeneration. This removes the competitive height advantage needed by shade-tolerant species to compete within gaps, and thus further promotes the opportunity for pioneer species to dominate gap regeneration. These observed differences between anthropogenic and natural tree-fall gaps are of direct importance to forest managers attempting to understand how disturbance associated with reduced-impact logging influences the regeneration of commercial tree species in Bolivian forestry concessions. We discuss the ecological and silvicultural implications of these results.

Commercial tree regeneration 6 years after high-intensity burns in a seasonally dry forest in Bolivia

The effects of three site-preparation treatments (high-intensity burn, low-intensity burn, and mechanical cleaning with machetes and chainsaws) on the regeneration of commercial tree species, composition and structure of competing vegetation, and soil chemical and structural properties were evaluated in a seasonally dry forest in southeast Bolivia. Six years after controlled burns, the high-intensity burn treatment had the both the highest density and the tallest individuals of shade-intolerant commercial tree species. Competing vegetation was also less dominant in the high-intensity burn treatment relative to other treatments. However, high-intensity burns were not beneficial for commercial tree species with shade-tolerant or intermediate regeneration. Soil analyses revealed that certain changes in soil texture and soil chemistry (e.g., Ca and Mg concentrations and cation exchange capacity) caused by high-intensity burns persisted 6 years after the fires. These findings confirm that this suite of shade-intolerant commercial species requires very intense disturbances for their regeneration. However, several ecological, economic, and social barriers currently preclude the management-scale application of prescribed fire in Bolivia. More research is needed on cost-effective treatments to improve regeneration.

Mechanical cleaning and prescribed burning for recruiting commercial tree regeneration in a Bolivian dry forest

A critical component of sustainable forest management is the regeneration of commercially valuable tree species. Mechanical cleaning with machetes and chainsaws, prescribed burning, and a combination of both treatments were applied to recently-created logging gaps in a Bolivian dry forest to evaluate their impact on the natural regeneration of commercial tree species and on control of competing vegetation. The three treatments and an untreated control were applied to logging gaps during the dry season of 1998 and replicated ten times. Eight months following burning, the density of commercial tree regeneration in gaps did not differ statistically among treatments. Relative height growth of total commercial regeneration also did not differ among treatments, although it did vary by species. Reduction in competing vegetation following the application of site preparation treatments was significantly higher, but competing plant cover was beginning to converge among treatments after eight months. Despite better control of competing vegetation, early recruitment and growth responses to burning and cleaning of vegetation in logging gaps do not appear to justify application of these treatments in this forest, especially considering their high costs.

Effects of partial overstory removal on the natural regeneration of a tropical forest in Quintana Roo, Mexico

In a tropical, semi-evergreen forest in Quintana Roo, Mexico, a study was conducted to observe the effects of partial overstory removal (creation of multiple gaps) on natural regeneration, with special attention to commercially valuable tree species. Five 0.5-ha plots were subjected to different levels of overstory removal of 0%, 8%, 28%, 45% and 55%. The regeneration population 3 years after overstory removal was similar in density and composition to the population before overstory removal except for an unidentified liana that was not found in 1986 but was moderately abundant in 1989. Regeneration of commercial tree species (tolerant and intolerant), noncommercial tree species, and nontree species was compared with the residual basal area and percentage of basal area removed. Frequency of intolerant commercial species increased as residual basal area decreased. Frequency of tolerant commercial species was not affected by residual basal area or percentage of basal area reduced.