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Population distribution and threats to sustainable management of selected non-timber forest products in tropical lowland rainforests of south western Nigeria

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Journal of forestry Research 2013年第1期24卷 75-82页

作者： Jimoh S.O. Amusa T.O. I.O. Azeez Department of Forest Resources Management University of IbadanNigeria. Department of Forest Resources Management University of IlorinNigeria.

Uncontrolled harvesting of non-timber forest products （NTFPs） poses a serious risk of extermination to several of these species in Nigeria. Yet, there is a paucity of information on the distribution, population status and sustainable management of NTFPs in most of the tropical lowland rainforests. We, therefore, assessed the population, distribution and threats to sustainable management of NTFPs within the tropical lowland rainforests of Omo and Shasha forest Reserves, south western Nigeria. Data were obtained through inventory surveys on five top priority species including： bush mango （Irvingia gabonensis （Aubry-Lecomte ex O’Rorke） Baill）, African walnut （Tetracarpidium conophorum （Mull. Arg.） Hutch. ＆ Dalziel syn. Plukenetia conophora）, chew-stick （Massularia acuminata （G. Don） Bullock）, fever bark （Annickia chlorantha Setten ＆ P.J.Maas syn. Enantia chloranta） and bush pepper （Piper guineense Schumach. ＆ Thonn.）. Purposive and stratified random sampling techniques were used for the inventory. Each forest reserve was stratified into three, viz： less disturbed natural forest （for areas that have been rested for at least ten years）, recently disturbed natural forest （for areas that have suffered one form of human perturbation or the other in the last five years）, and plantation forest （for areas carrying forest plantation）. Data were collected from eighteen 10 m × 500 m belt transects located in the above strata. The species were generally fewer in both plantation and recently disturbed natural forest than the less disturbed natural forest, suggesting that forest disturbances （habitat modification） for other uses may have an effect on the occurrence and densities of the NTFPs. Exceptions to this trend were found for P. guineense and T. conophorum, which were fairly common in both plantation and recently disturbed natural forest. Among three tree NTFP species （i.e. I. gabonensis, M. acuminata and A. chlorantha）, only I. gabonensis showed a significant difference in overall DBH size classes for both reserves （t=？2.4

关键词： Tropical rainforest non-timber forest products （NTFP） population density distribution forest management

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Radial and longitudinal density variations in Abies cephalonica and Pinus halepensis

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Journal of forestry Research 2023年第3期34卷 853-863页

作者： Vasiliki Dimou Anna Tsaliki Kyriaki Kitikidou Laboratory of forest Technology Department of Forestry and Management of the Environment and Natural ResourcesDemocritus University of Thrace193 Pandazidou68200 OrestiadaPCGreece Laboratory of forest Biometry-Biostatistics Department of Forestry and Management of the Environment and Natural ResourcesDemocritus University of Thrace193 Pandazidou68200 OrestiadaPCGreece

Basic wood density is an excellent indicator of quality,it is correlated with numerous physical,physiological and mechanical characteristics of a species and is a good descriptor of wood quality and important indicator of tree performance in community ecology.An accurate method is thus needed to estimate wood density.The standard way is to calculate the ratio of the oven-dried mass of a wood sample divided by its green volume,but wood characteristics within and between growth rings are highly variable;the density can vary in the longitudinal and the radial directions.The present study investigates the longitudinal and radial fl uctuations in the basic density of Abies cephalonica Loud and Pinus halepensis Mill.Four logs were cut from four diff erent trees for each species and 16 discs were formed(two discs from each log,one at the base and one at the top).Each disc was cut into cubes where their distance from the pith was measured and then sorted into 2 cm wide concentric zones.The results revealed a mild decreasing trend in basic density from the foot of the trunk upward for both species.The pith in both species also seems to have a relatively high density,which in the immediate next growth rings decreases only to resume increasing toward the bark.

关键词： Aleppo pine Physical properties Specifi c gravity Wood quality

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Impacts of COVID-19 on tourism and management response from Banff National Park,Canada

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林业研究:英文版 2023年第5期34卷 1229-1244页

作者： Christina Dehui Geng Howie WHarshaw Wanli Wu Guangyu Wang Department of Forest Resources Management Faculty of ForestryUniversity of British ColumbiaVancouverCanada Faculty of Kinesiology Sportand RecreationUniversity of AlbertaEdmontonCanada

The COVID-19 pandemic posed challenges to the tourism sector globally.We investigated changes in visitor demographics,satisfaction level,and its determinants pre-and peri-COVID-19.Data were collected using questionnaire surveys in 2019 and 2021 within Banff National Park(BNP).The data analyses were based on a sample size of 1183 respondents by conducting factor analysis,correlation analysis and stepwise regression analysis.Results highlight that there were fewer international visitors and more local and domestic visitors during the pandemic.Park attributes were evaluated at a higher satisfaction level peri-COVID-19.The quality of the Park facilities and services were the most important satisfaction determinants pre-and peri-COVID-19,and all the Park COVID-19 measures and actions received positive experience from visitors.This research fills this knowledge gap by developing a better understanding in the change of visitor demographics and satisfaction level in BNP under the context of the pandemic.It also provides implication for both scholars and practitioners to understand the impacts of the pandemic on Park visitation.The study can provide insights for utilizing the pandemic as a transformative strength and for mitigating its negative impact on tourism industry.

关键词： National park COVID-19 pandemic Visitor experience Tourism management Visitor perception

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Stand-level biomass models for predicting C stock for the main Spanish pine species

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forest Ecosystems 2021年第2期8卷 387-402页

作者： Ana Aguirre Miren del Río Ricardo Ruiz-Peinado Sonia Condés department of Natural Systems and resources School of Forest Engineering and Natural ResourcesUniversidad Politécnica de MadridMadridSpain INIA Forest Research CenterDepartment of Forest Dynamics and ManagementMadridSpain iuFOR Sustainable Forest Management Research InstituteUniversity of Valladolid and INIAValladolidSpain

Background:National and international institutions periodically demand information on forest indicators that are used for global reporting.Among other aspects,the carbon accumulated in the biomass of forest species must be reported.For this purpose,one of the main sources of data is the National forest Inventory(NFI),which together with statistical empirical approaches and updating procedures can even allow annual estimates of the requested indicators.Methods:Stand level biomass models,relating the dry weight of the biomass with the stand volume were developed for the five main pine species in the Iberian Peninsula(Pinus sylvestris,Pinus pinea,Pinus halepensis,Pinus nigra and Pinus pinaster).The dependence of the model on aridity and/or mean tree size was explored,as well as the importance of including the stand form factor to correct model bias.Furthermore,the capability of the models to estimate forest carbon stocks,updated for a given year,was also analysed.Results:The strong relationship between stand dry weight biomass and stand volume was modulated by the mean tree size,although the effect varied among the five pine species.Site humidity,measured using the Martonne aridity index,increased the biomass for a given volume in the cases of Pinus sylvestris,Pinus halepensis and Pinus nigra.Models that consider both mean tree size and stand form factor were more accurate and less biased than those that do not.The models developed allow carbon stocks in the main Iberian Peninsula pine forests to be estimated at stand level with biases of less than 0.2 Mg·ha^(-1).Conclusions:The results of this study reveal the importance of considering variables related with environmental conditions and stand structure when developing stand dry weight biomass models.The described methodology together with the models developed provide a precise tool that can be used for quantifying biomass and carbon stored in the Spanish pine forests in specific years when no field data are available.

关键词： Martonne aridity index Dry weight biomass Carbon stock National forest Inventory Peninsular pine forest Biomass expansion factor

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A review of the effects of forest fire on soil properties

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Journal of forestry Research 2022年第5期33卷 1419-1441页

作者： Alex Amerh Agbeshie Simon Abugre Thomas Atta-Darkwa Richard Awuah department of Environmental management University of Energy and Natural Resources(UENR)SunyaniGhana department of forest Science University of Energy and Natural Resources(UENR)SunyaniGhana department of Mechanical and Manufacturing Engineering University of Energy and Natural Resources(UENR)SunyaniGhana

forest fires are key ecosystem modifiers affecting the biological,chemical,and physical attributes of forest soils.The extent of soil disturbance by fire is largely dependent on fire intensity,duration and recurrence,fuel load,and soil characteristics.The impact on soil properties is intricate,yielding different results based on these factors.This paper reviews research investigating the effects of wildfire and prescribed fire on the biological and physico-chemical attributes of forest soils and provides a summary of current knowledge associated with the benefits and disadvantages of such fires.Low-intensity fires with ash deposition on soil surfaces cause changes in soil chemistry,including increase in available nutrients and pH.High intensity fires are noted for the complete combustion of organic matter and result in severe negative impacts on forest soils.High intensity fires result in nutrient volatilization,the break down in soil aggregate stability,an increase soil bulk density,an increase in the hydrophobicity of soil particles leading to decreased water infiltration with increased erosion and destroy soil biota.High soil heating(> 120℃) from high-intensity forest fires is detrimental to the soil ecosystem,especially its physical and biological properties.In this regard,the use of prescribed burning as a management tool to reduce the fuel load is highly recommended due to its low intensity and limited soil heating.Furthermore,the use of prescribed fires to manage fuel loads is critically needed in the light of current global warming as it will help prevent increased wildfire incidences.This review provides information on the impact of forest fires on soil properties,a key feature in the maintenance of healthy ecosystems.In addition,the review should prompt comprehensive soil and forest management regimes to limit soil disturbance and restore fire-disturbed soil ecosystems.

关键词： forest fires Low-severity fire Mineralization Soil available nutrients Soil organic matter Volatilization

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Integrating volunteered smartphone data with multispectral remote sensing to estimate forest fuels

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International Journal of Digital Earth 2016年第2期9卷 171-196页

作者： Colin J.Ferster Nicholas C.Coops Department of Forest Resources Management University of British ColumbiaVancouverBCCanada

Volunteered data sources are readily available due to advances in electronic communications technology.For example,smartphones provide tools to collect ground-based observations over broad areas from a diverse set of data collectors,including people with,and without,extensive training.In this study,volunteers used a smartphone application to collect ground-based observations.forest structural components were then estimated over a broader area using high spatial resolution RapidEye remote sensing imagery(5 spectral bands 440–850 nm,5 m spatial resolution)and a digital elevation model following a three nearest neighbor approach(K-NN).Participants with professional forestry experience on average chose highpriority fuel load locations near buildings,while nonprofessional participants chose a broader range of conditions over a larger extent.When used together,the professional and nonprofessional observations provided a more complete assessment of forest conditions.A generalized framework is presented that utilizes K-NN imputation tools for estimating the distribution of forest fuels using remote sensing and topography variables,ensuring spatial representation,checking attribute accuracy,and evaluating predictor variables.Frameworks to integrate volunteered data from smartphone platforms with remote sensing may contribute toward more complete Earth observation for Digital Earth.

关键词： citizen science public participation in scientific research mobile RapidEye red edge WUI

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A comprehensive review of the effects of biochar on soil physicochemical properties and crop productivity

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Waste Disposal and Sustainable Energy 2022年第4期4卷 343-359页

作者： Ammal Abukari James Seutra Kaba Evans Dawoe Akwasi Adutwum Abunyewa department of Agroforestry Kwame Nkrumah University of Science and TechnologyKumasiGhana department of forestry and forest resources management University for Development StudiesTamaleGhana

Intensive land use has several detrimental effects on land function and imposes an undue burden on the environment.Continuous farming and pollution by heavy metals have negatively influenced many soils.Biochar is now gaining attention as a major research subject in the areas of agriculture,environment,and energy as an eco-friendly soil conditioner.The use of biochar for agricultural and environmental purposes has been widely studied and reviewed.Unfortunately,there are few reviews on biochar structures and other biochar uses.This review presents an overview of current developments in the effects of numerous biochar physicochemical properties and biochar uses,such as utilization as a soil microbial activity,contaminant adsorbent,ion exchange,soil amendment,gas storage and water retention.The physical,chemical and biological properties have been discussed following amendments to the soil and conditions of preparation.However,scientific observation and research are required to identify the negative effects of biochar in preparations and applications.It is envisaged that further in-depth studies of biochar amendment will lead to a deeper understanding of biochar's relationships with soils and that reviews of the negative impacts of biochar could reveal ways in which they might be mitigated.

关键词： Biochar Hydraulic properties Soil properties Negative effect Modification Crop yield

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Estimating upper stem diameters and volume of Douglas-fir and Western hemlock trees in the Pacific northwest

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forest Ecosystems 2018年第3期5卷 199-210页

作者： Krishna P.Poudel Hailemariam Temesgen Andrew N.Gray department of forest Engineering Resources and Management College of Forestry Oregon State University USDA forest Service PNW Research Station

Background: Volume and taper equations are essential for obtaining estimates of total and merchantable stem volume. Taper functions provide advantages to merchantable volume equations because they estimate diameter inside or outside bark at specific heights on the stem, enabling the estimation of total and merchantable stem volume, volume of individual logs, and a height at a given diameter.Methods: Using data collected from 1218 trees(1093 Douglas-fir(Pseudotsuga menziesii(Mirbel) Franco) and 125 western hemlock(Tsuga heterophylla)), we evaluated the performance of one simple polynomial function and four variable-exponent taper functions in predicting upper stem diameter. Sample trees were collected from different parts of the states of Oregon, Washington, and California. We compared inside-bark volume estimates obtained from the selected taper equation with estimates obtained from a simple logarithmic volume equation for the data obtained in this study and the equations used by the forest Inventory and Analysis program in the Pacific Northwest(FIA-PNW) in the state of California and western half of the states of Oregon and Washington.Results: Variable exponent taper equations were generally better than the simple polynomial taper equations.The FIA-PNW volume equations performed fairly well but volume equations with fewer parameters fitted in this study provided comparable results. The RMSE obtained from taper-based volume estimates were also comparable with the RMSE of the FIA-PNW volume equations for Douglas-fir and western hemlock trees respectively.Conclusions: The taper equations fitted in this study provide added benefit to the users over the FIA-PNW volume equations by enabling the users to predict diameter at any height, height to a given diameter, and merchantable volume in addition to cubic volume including top and stump(CVTS) of Douglas-fir and western hemlock trees in the Pacific Northwest. The findings of this study also give more confidence to the users of FIA-PNW volume equations.

关键词： Pacific northwest Biomass equations Utilization standards Diameter inside bark

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Comparison of stem volume estimates from terrestrial point clouds for mature Douglas-fir(Pseudotsuga menziessi(Mirb.)Franco)

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Information Processing in Agriculture 2023年第3期10卷 334-346页

作者： Rong Fang Bogdan M.Strimbu forest Engineering Resourcesand Management DepartmentOregon State UniversityCorvallisOR 97333 ORUSA

As a complement to traditional estimates of stem dimensions from numerical models,terrestrial light detection and ranging(Lidar)provides direct stem diameter and volume values using cylindrical models constructed from point clouds.This study used two approaches to estimate total stem volume using Lidar and compared them with two empirical equations,one used by the forest Inventory Analysis in the Pacific Northwest(FIA-PNW)and one based on a taper equation.We fitted point clouds of 10 Douglas-fir with three sets of cylinder models that are distinguished by their segment length(i.e.0.5 m,1 m,and 2 m),then developed three taper equations based on the point-cloud-based diameter estimated previously.We estimated the total stem volume of the tree with eight models:six-point cloudbased(i.***.three taper and three cylinders)and two empirical.Finally,we used simulations to extrapolate the volume estimations of various methods for different diameters at breast height(DBH)classes.We found that all the point-cloud-based taper equations were similar in their performance(R2¼0:94,RMSE=4.6 cm)and produced mean volume estimates greater than mean estimates of the existing models.The cylinder models produced 11–16%greater mean volume estimates than the FIA-PNW estimate,with the 0.5 m segment length producing the greatest values,followed by the 1 m and 2 m segment length.The simulated data suggested that the mean volume estimates of a given DBH class are different when using different computation methods.ANOVA revealed a combined effect of the computation methods and the DBH class on the mean volume estimates.We conclude that the point-cloud-based taper equations,after being symmetrically calibrated,would be consistent with the regional stem volume estimates,whereas the cylinder models would be better in estimating individual stem volume.When constructing Lidar-based cylinder models in future applications,cylinder segment length would need to be adjusted to the length and DBH of the stem,as well as to the objectives of the research.

关键词： Lidar Cylinder models Cylinder segment length Taper equations forest inventory and analysis

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Drivers of spatial structure in thinned forests

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forest Ecosystems 2024年第2期11卷 202-213页

作者： Zichun Wang Yaoxiang Li Guangyu Wang Zheyu Zhang Ya Chen Xiaoli Liu Rundong Peng College of Mechanical and Electrical Engineering Northeast Forestry UniversityHarbin150040China Department of Forest Resources Management University of British ColumbiaVancouverCanada

Background:As is widely known,an increasing number of forest areas were managed to preserve and enhance the health of forest ecosystems.However,previous research on forest management has often overlooked the importance of structure-based.Aims:Our objectives were to define the direction of structure-based forest management.Subsequently,we investigated the relationships between forest structure and the regeneration,growth,and mortality of trees under different thinning treatments.Ultimately,the drivers of forest structural change were explored.Methods:On the basis of 92 sites selected from northeastern China,with different recovery time (from 1 to 15years) and different thinning intensities (0–59.9%) since the last thinning.Principal component analysis (PCA)identified relationships among factors determining forest spatial structure.The structural equation model (SEM)was used to analyze the driving factors behind the changes in forest spatial structure after thinning.Results:Light thinning (0–20%trees removed) promoted forest regeneration,and heavy thinning (over 35% of trees removed) facilitated forest growth.However,only moderate thinning (20%–35%trees removed) created a reasonable spatial structure.While dead trees were clustered,and they were hardly affected by thinning intensity.Additionally,thinning intensity,recovery time,and altitude indirectly improve the spatial structure of the forest by influencing diameter at breast height (DBH) and canopy area.Conclusion:Creating larger DBH and canopy area through thinning will promote the formation of complex forest structures,which cultivates healthy and stable forests.

关键词： Thinning Natural secondary forest Spatial structure Dynamic changes Growth factors Structural equation modeling

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