受极端高温天气影响,全球近年来森林火灾频发.2022年我国南方地区遭遇1961年以来最严重的气象干旱,四川、湖南、江西和广西等地受持续高温干旱影响,森林火灾呈多发态势.以2022年桂林市全州县"10·17"森林火灾为例,基于哨兵2号和中巴地球资源卫星04A星3期遥感影像、无人机航拍影像、气象数据及森林火灾后的实地调查数据,通过分析气象条件、林分干旱胁迫程度和干旱胁迫对林分受害程度的影响,探讨林分干旱胁迫程度与火灾受损程度间的关系.结果表明,森林火灾发生前研究区受干旱胁迫影响明显;干旱胁迫对杉木(Cunninghamia lanceolata)林分火灾受损程度影响较大,近50%的火烧迹地杉木林分遭受不同程度干旱胁迫;干旱胁迫加重各龄组杉木林分重度受害程度.基于遥感影像的NDVI值能准确反映林分受干旱胁迫程度;建议充分发挥遥感影像在火灾监测、火险评估和灾后恢复等方面的潜力和优势,结合气象数据,实现极端气候条件下火险的准确评估和预测,为火灾预防和应急决策提供科学依据.

为科学评价广西公益林建设和保护成效,根据广西公益林森林资源连续监测数据,依据《森林生态系统服务功能评估规范》(GB/T 38582-2020),对广西2012、2017和2022年公益林的森林生态系统服务价值进行评估.结果表明,2012、2017和2022年,广西公益林森林生态系统服务价值以固碳释氧、涵养水源和生物多样性为主,占总服务价值的82.40%～83.95%;其次为保育土壤和净化大气环境,占15.13%～16.68%;林木养分固持服务价值最低,占0.89%～0.93%.天然阔叶林和灌木林生态系统服务价值较高,其次为松树(Pinus spp.)林、杉木(Cunninghamia lanceolata)林和竹林,桉树(Eucalyptus spp.)林和经济乔木林较低.天然阔叶林单位面积服务价值最高,其次为杉木林、松树林、桉树林和竹林,经济乔木林和灌木林较低.2012、2017和2022年广西公益林森林生态系统服务总价值分别为 3 724.16亿元、3 856.49亿元和4 530.83亿元,单位面积服务价值分别为7.18万元/公顷、7.58万元/公顷和9.03万元/公顷.广西公益林森林生态系统服务功能不断增强,服务价值稳步提高,公益林生态建设和保护成效明显.

Understanding the main driving factors of forest fires and predicting the occurrence of forest fires can provide scientific basis for the prevention and management of local forest fires.Based on the historical fire data sets,meteorology,topography,human activities and combustible load data from 2011 to 2020,we built Logistic regression models and machine learning models to explore the main driving factors of forest fires in Guangxi.Additionally,the optimal model was selected to predict the probability of forest fire occurrences in the research area.The result showed that average monthly rainfall,average monthly relative humidity and the number of forest buildings were the most significant factors affecting the occurrence of forest fires in Guangxi.Both Logistic regression model and machine learning model had excellent prediction accuracy,with AUC values above 0.85.The accuracy of the machine learning model was better than Logistic regression model,and the random forest model had the highest accuracy(SAUC=0.92).The random forest model showed that the risk of forest fires was greatest in northwest,northern and southwestern regions of Guangxi.The overall results of the model were consistent with the actual situation in Guangxi and can provide a reference for forest fire prediction and forecasting in Guangxi.In the future,managers should strengthen the control of wild fire sources and prevention capabilities of extreme weather to reduce the risk of forest fires.

以2011年石漠化监测数据为基础,叠加处理后的遥感影像,对2016年靖西市发生变化的石漠化图斑进行区划与解译,再实地核准界线,调查监测因子,通过对空间属性数据发生变化的图斑进行汇总统计,获取全市本期石漠化土地面积及分布信息,并与前期数据进行对比分析.结果表明,靖西市石漠化土地面积减少16977.52 hm2;由石漠化转变为潜在石漠化的顺向演替面积为17371.72 hm2,为石漠化土地减少的主导方面.在前后两期均为石漠化的土地中属于改善型和退化型面积分别为2804.45 hm2和1417.61 hm2,主导因素分别为林草治理措施和人为破坏因素,全市石漠化总体呈现顺向演替的态势.

以广西中越边境地区为研究区,在实地区划调查数据的基础上,区划自然阻隔带、生物阻隔带区段,筛选适宜建设生物防火林带的区段,运用ArcGIS确定其空间分布格局,本次规划将新建50m宽标准防火林带林地178.94km.

对广西凤山县石漠化不同植被恢复模式的土壤理化性质进行测定分析,结果表明:随着植被的恢复,其石漠化的土壤肥力效应有明显的变化,其土壤容重降低6.1％～16.8％,土壤总孔隙度增加7.5％～14.2％,土壤有机质含量增加21.4％～32.7％,水解氮含量增加32.2％～55.6％,土壤有效磷含量增加77.1％～144.6％,土壤速效钾含量增加15.2％～ 35.7％,但都随着土层深度的增加而减弱.不同植被恢复模式对土壤肥力效应的影响序列为任豆(Zenia insignis)-构树(Broussonetia papyrifera)模式＞任豆纯林模式＞香椿(Toonasinensis)-金银花(Lonicera japonica)模式＞任豆-山葡萄(Cayratia corniculata)模式.

Through the introduction of status of forest expropriation management in Guangxi Province,and analysis of the problems in management,the author put forward measures such like: strengthen the propaganda and education,strengthen law enforcement,perfecting management system,and reform the quota management system of forest land expropriation.

In the paper,the annual growth productions of Acacia concinnata test plantation were measured and calculated,with the collection and analyses of its litter.The result showed that :①The litter productions of 2～5 years old Acacia concinnata regressed to the land were 12208 kg/hm2 in the 2003～2005,and there were averagely 1017 kg/hm2 litter productions regressing to the land every month.②For the whole year,the highest annual litter production(the leaves) of Acacia concinnata stand in 3 years old,4 years old and 5 years old were all in October,the lowest ones were all in march.In 2003,the highest mensal litter production was 1411 kg/hm2,and the lowest was 16 kg/hm2.The average mensal litter production was 374 kg/hm2.In 2004,the highest mensal litter production was 1216 kg/hm2,and the lowest was 8 kg/hm2.The average mensal litter production was 320.7 kg/hm2.In 2005,the highest mensal litter production was 647.8 kg/hm2,and the lowest was 56 kg/hm2.The average mensal litter production was 322.6 kg/hm2.And the larger stand age,the more mensal litter production which month the highest mensal litter production was in.③The annual litter production was connected with the growth of the stand height and DHB.The larger stand age,the lower growth of the stand height and DHB.And increasing 1m with height and 1cm with DHB,the annual litter production needed was more and more.④The annual litter production was connected with the growth of the stand volume.The larger stand age,the lower growth of the stand volume.And increasing 1m3 with volume,the annual litter production needed was less and less.The annual litter production affected the volume,but it had little effect.

In order to prepare the forest land protection and utilization planning for Shangsi County in Guangxi province,woodland in small classes in this region were conduted one by one for quality grading assessment.According to the forest distribution and growth performance,7 indices were selected as the factors for the woodland rating factors including thickness of the soil,altitude,slope,aspect,slope position,gravel content,traffic location,taking the quantification theory I as the modeling tool.Results of the study tally well with the actual situation,and thus meet well the requirement for the preparation of forest protection and utilization planning and provide theoretical basis for the selection of reforestation species.