Effects of harvest intensity on the marketable organ yield, growth and reproduction of non-timber forest products (NTFPs): implication for conservation and sustainable utilization of NTFPs

Background Non-timber forest products (NTFPs) are an important part of forest biodiversity, and the subsistence and trade of local people, especially in less developed countries. Because of the high ecological and economic value, NTFPs have faced the problem of over-exploitation, and the key to solve this problem is to determine the feasible way of sustainable utilization of NTFPs. Harvest intensity is one of the most important and easily controlled utilization factors, which can greatly influence the plant individual survival, growth and reproductive performances, and even the population structure and dynamics. Therefore, we chose two common and important NTFPs species with different marketable parts (i.e., Acanthopanax senticosus with tender leaves and Aralia elata with tender buds) as our study objects. Aiming to determine the optimum harvest intensity for sustainably utilizing both NTFPs species, five levels of harvest intensity treatments (i.e., control, light, medium, high and severe) were designed to assess the effects of harvest intensity on their marketable organ yield, plant growth and reproductive performances. Results The biomass growth rates of marketable organ and plant growth of A. senticosus under light harvest intensity treatment were significantly higher than those under other harvest intensities. The plant height growth and 1000-seed weight of A. elata under severe harvest intensity treatment were significantly lower than those under control treatment. Conclusions The light harvest intensity with 25% leaf removal and the high harvest intensity with all terminal buds harvested are the optimum harvest intensity to maintain the sustainable utilization of A. senticosus and A. elata, respectively. These findings could provide managers with basic but practical guidance for making decisions about the sustainable harvest management plan for the cultivated NTFPs species, and further provide a theoretical basis for managers to establish the harvest regulations for wild NTFPs species. Consequently, the local residents or communities can improve their income while ensure the sustainable development of wild NTFPs.

PENGARUH SUBSTITUSI SERBUK ECENG GONDOK DAN AMPAS TEMPE TERHADAP PRODUKSI JAMUR TIRAM PUTIH (Pleurotus ostreatus)

In general, the basic material used in the planting media of white oyster mushroom is sawdust. The increasing need for sawdust, without being offset by sufficient availability will make sawdust difficult to obtain. The research aimed to obtain the composition substitution of the hyacinth powder and tempe dregs which provided the highest results for growth and yield of white oyster mushroom (Pleurotus ostreatus). The research was conducted in Gintung Kerta Village, Klari Subdistrict, Karawang District, West Java from July 2020 to October 2020. The method used was an experimental method with used Randomized Block Design (RDB) single factor, consisting of 9 treatments and 3 replications so there were 27 experimental units. The treatments were: A (without the addition of growing media treatment); B (5% water hyacinth powder); C (10% water hyacinth powder); D (15% water hyacinth powder; E (20% water hyacinth powder); F (Tempe dregs 5%); G (Tempe dregs 10%); H (Tempe dregs 15%); and I (Tempe dregs 20%). The results showed that there was a significant effect of composition proportion substitution of the hyacinth powder and tempe dregs on the length of mycelium per baglog, maximum fruit hood diameter per baglog, harvest intensity per baglog, fresh weight of mushrooms per baglog, and total yield in a planting period. The treatment of H (Tempe dregs 15%) gave the highest yield to the harvest intensity of 2.44 times, the mushroom fresh weight of 89.42 g/baglog, and the total yield in a planting period of 408.00 g.

Synchronous changes in length at maturity across four species of Lake Erie fish with different harvest histories

Decreases in size at maturation in harvested fish populations can reduce productivity and resilience. Delineating the causes for these changes in maturation is challenging. We assessed harvest and large-scale ecosystem variability as causes for changes in maturation in four Lake Erie fishes. Regulated harvests of Yellow Perch (Perca flavescens) and Walleye (Sander vitreus) are greater than unregulated harvests of White Perch (Morone americana) and White Bass (Morone chrysops). Our assessment considered cohort data from 1991-2012 for each species. We used a conceptual model of harvest-induced plasticity to show that changes in female length at 50% maturity (L50) were unrelated to harvest intensity in all species. We then demonstrated that changes in female L50 among cohorts were synchronous across species. Post-hoc analysis of variables capturing year-to-year variation in climatic and lake conditions suggested L50 was larger when water levels were near the norm for the study period and smaller at low and high levels. We conclude that changes in L50 were most strongly related to ecosystem changes unrelated to harvest intensity.

Residual Trees Response to Selective Cutting Operations in Caspian Forests

Damages to residual trees caused by felling operation were assessed in the stands of a Caspian hardwood forest. Following the felling operation, a field survey was done to collect data of all residual trees (species, DBH, height) and of tree wounds (size class, location, intensity of damage). Different harvesting intensities were studied, and treatments were replicated three times. The results showed that the treatment with the medium and high harvest intensity was found to cause the highest percentage of damage and the largest stem wounds. It is concluded that harvesting intensity should be limited to 3 trees/ha during each harvesting operation to reduce the extent of tree damage and thus future financial loss.

Complex dynamics arising from the interplay between prey harvest saturation and predator-prey dynamics

A study of the influence of prey harvest saturation on the dynamics of a predator-prey system is undertaken. It is shown that the augmentation of the constant intensity harvest part of this functional response can significantly change prey-predator dynamics by means of slight variations of the constant harvest intensity, rendering thus species management difficult due to, for instance, multiple attractors. Given that some management policies rely on the harvest saturation structure studied in this work, these results may have significant implications regarding renewable resource management.

A simple grid-based framework for simulating forest structural trajectories linked to transient forest management scenarios in Fennoscandia

Forest structural properties largely govern surface fluxes of moisture, energy, and momentum that strongly affect regional climate and hydrology. Forest structural properties are greatly shaped by forest management activities, especially in the Fennoscandia (Norway, Sweden, and Finland). Insight into transient developments in forest structure in response to management intervention is therefore essential to understanding the role of forest management in mitigating regional climate change. The aim of this study is to present a simple grid-based framework – the Fennoscandic Forest State Simulator (F2S2) -- for predicting time-dependent forest structural trajectories in a manner compatible with land models employed in offline or asynchronously coupled climate and hydrological research. F2S2 enables the prescription of future regional forest structure as a function of: i) exogenously defined scenarios of forest harvest intensity; ii) forest management intensity; iii) climate forcing. We demonstrate its application when applied as a stand-alone tool for forecasting three alternative future forest states in Norway that differ with respect to background climate forcing, forest harvest intensity (linked to two Shared Socio-economic Pathways (SSPs)), and forest management intensity. F2S2 captures impacts of climate forcing and forest management on general trends in forest structural development over time, and while climate is the main driver of longer-term forest structural dynamics, the role of harvests and other management-driven effects cannot be overlooked. To our knowledge this is the first paper presenting a method to map forest structure in space and time in a way that is compatible with land surface or hydrological models employing sub-grid tiling.