Combining harvest sample data with inventory data to estimate forest biomass

Forest biomass databases which go beyond stem volume are needed for carbon balance calculations and also for forest monitoring, forest damage inventories and the solution of other related problems. In this article, it is shown how recursive multiple regression analysis can combine forest inventory data with biomass harvest data. The stand‐level conversion factor derived for Pinus sylvestris L. branch biomass for the “Severka”; Forest Farm shows a reasonable goodness of fit, with a coefficient of determination of R² = 0.87. Statistically significant coefficients were achieved by including stand density and the quadratic mean diameter in the regression. Equations developed for Switzerland, using Burger's Picea abies (L.) Karst. branch and needle conversion factors for individual trees, show R² = 0.87 and R ² = 0.91, achieved by taking h _dom.50, elevation, diameter at breast height and age into account.     

广州市森林火险性天气预报研究

广州市地处亚热带季风气候区．城市森林面积大，人口密集，极易发生森林火灾，利用广州市1997～2001年火险性天气资料，结合各季节人为用火影响规律，参照全国森林火险性天气预报方法，研制了广州市短期森林火险性天气预报系统，并利用森林火险天气预报系统自动生成广州市森林火险天气等级分布图．以此为依据来发布广州市各区(县、市)短期森林火险天气预报，     

A comparison of landscape fuel treatment strategies to mitigate wildland fire risk in the urban interface and preserve old forest structure

We simulated fuel reduction treatments on a 16,000 ha study area in Oregon, US, to examine tradeoffs between placing fuel treatments near residential structures within an urban interface, versus treating stands in the adjacent wildlands to meet forest health and ecological restoration goals. The treatment strategies were evaluated by simulating 10,000 wildfires with random ignition locations and calculating burn probabilities by 0.5 m flame length categories for each 30 m × 30 m pixel in the study area. The burn conditions for the wildfires were chosen to replicate severe fire events based on 97th percentile historic weather conditions. The burn probabilities were used to calculate wildfire risk profiles for each of the 170 residential structures within the urban interface, and to estimate the expected (probabilistic) wildfire mortality of large trees (>53.3 cm) that are a key indicator of stand restoration objectives. Expected wildfire mortality for large trees was calculated by building flame length mortality functions using the Forest Vegetation Simulator, and subsequently applying these functions to the burn probability outputs. Results suggested that treatments on a relatively minor percentage of the landscape (10%) resulted in a roughly 70% reduction in the expected wildfire loss of large trees for the restoration scenario. Treating stands near residential structures resulted in a higher expected loss of large trees, but relatively lower burn probability and flame length within structure buffers. Substantial reduction in burn probability and flame length around structures was also observed in the restoration scenario where fuel treatments were located 5–10 km distant. These findings quantify off-site fuel treatment effects that are not analyzed in previous landscape fuel management studies. The study highlights tradeoffs between ecological management objectives on wildlands and the protection of residential structures in the urban interface. We also advance the application of quantitative risk analysis to the problem of wildfire threat assessment.     

Canopy fuel characteristics in relation to crown fire potential in pine stands: analysis, modelling and classification

Crown fire occurrence and subsequent crown fire behaviour are strongly dependent on canopy fuel characteristics, especially canopy fuel load (CFL), canopy bulk density (CBD) and canopy base height (CBH). Therefore, quantification of such variables is required for the appropriate selection of silvicultural treatments aimed at reducing susceptibility to crown fire. Data from the IV Spanish National Forest Inventory and individual tree biomass dry weight equations were used to estimate the canopy fuel characteristics of four representative types of pine stands in north-western Spain. Probability of crown fire initiation and crown fire rate of spread were simulated by using the mean surface fuel load observed for each type of pine in this area and assuming different burning conditions. The results indicate that a 22.13 % of the sample plots analysed showed a rather high potential for active crown fire spread under moderate burning conditions, and this value increases to 69.27 % under extreme burning conditions. Equations relating the canopy fuel characteristics to common stand variables (stand density, basal area and dominant height) were fitted simultaneously for each pine, and weighting factors for heteroscedasticity were included. The models explained more than 93.90, 74.70 and 69.42 % of the observed variability in CFL, CBD and CBH, respectively. Basal area was the most important variable for estimating CFL and CBD while dominant height explained most of the observed variability in CBH. The use of the fitted equations together with existing dynamic growth models and fire management decision support systems will enable assessment of the crown fire potential associated with different silvicultural alternatives used in these types of pine stands.     

Compilation of a European forest map from Portugal to the Ural mountains based on earth observation data and forest statistics

This article focuses on the approach of combining the information from both remote sensing and forest inventory statistics in order to produce a European forest proportion map covering the area from Portugal to the Ural mountains. For this purpose, a calibration method was developed, tested and applied to the pan-European area. The resulting forest map was analysed on a pixel-by-pixel basis and given to inventory and remote sensing experts for consultation. When comparing both the result of the calibrated forest map with that of the original AVHRR mosaic of the area it was found that the satellite-derived estimates of forest area closely matched the ground inventory statistics indicating the high accuracy obtained from the AVHRR mosaic alone. Most visible discrepancies were found in northern Europe where the inventory data showed less forest than the image data. In southern Europe, the inventory data displayed more forest than the AVHRR image. This project was carried out for the European Commission, Joint Research Centre in 1999/2000 (contract no. 17223-2000-12 F1SC ISP FI) mainly by the European Forest Institute and VTT Information Technology.     

Quantifying fine fuel dynamics and structure in dry eucalypt forest (Eucalyptus marginata) in Western Australia for fire management

Techniques for rapid visual assessment of fuel characteristics have a broad range of applications in wildland fire management and research. We developed and tested a technique for assessing forest fuels which provides hazard ratings for distinct layers within the overall fuel complex, including bark, elevated shrubs, near-surface and surface (forest litter) fuels. These layers are comprised predominantly of fine fuel particles <6 mm diameter. The technique was used to model fuel accumulation in dry eucalypt forest of Eucalyptus marginata at two locations with contrasting understorey structures. We found that visual fuel hazard ratings described patterns of fuel dynamics over time in a similar fashion to models for fuel load accumulation. Visual hazard ratings can be related qualitatively to factors that reflect the difficulty of fire suppression by experienced fire fighters including visibility through the forest, access, difficulty of working machinery, flame height and spotting potential. The ability to relate hazard ratings to fire spread prediction needs to be tested.     

地被可燃物与林型火险等级划分

采用模糊聚类分析方法，以辽宁省各地区常见的主要林型37个为聚类单元，选取各聚类单元中的林火发生频度、地被可燃物载量、可燃物含水率、凋落物层厚度、可燃物燃烧蔓延速度作为聚类因子，进行全省林型火险等级划分。聚类分析结果划分出了不同火险级别（Ⅰ-Ⅳ）林型，并详细列出Ⅰ、Ⅱ、Ⅲ级火险林型在省内分布情况。     

加强森林防火统计工作实现森林防火工作信息化--在全国森林防火统计软件和网络传输技术培训班上的讲话(摘要)

7月下旬,我们在云南省昆明市举办了全国森林防火业务研讨培训班,对春防工作进行了简要回顾,对下半年和近一时期的工作进行了布置。下半年和近期的主要工作是,编制“十五”计划和15年远景规划,制定和实施重点火险区综合治理方案,准备修改《森林防火条例》,研究建立森林防火标准化组织和体系,开展防火资金使用管理的检查和抽查工作,全力做好秋（冬）季森林防火工作。这些工作任务都很重,对今后防火事业发展走向有很重要的意义,所以在这次会上,我们提出今后防火发展的大化：科学化、法制化、规范化、标难化、信息化、专业化。当前…     

数据融合技术在"3S"森林防火中的应用

本文首先阐明了森林防火对人类实现“可持续发展”战略的重大意义 ;继而在简介“3S” (RS、GIS与GPS)系统的基本原理的基础上 ,进一步介绍了MODIS卫星红外遥感技术对森林防火技术的提升 ,并对其不足之处提出了“数据融合”技术的改进方法 ,最后展望了森林防火工作的未来发展前景。     

Short-term response of reptiles and amphibians to prescribed fire and mechanical fuel reduction in a southern Appalachian upland hardwood forest

We compared the effects of three fuel reduction techniques and a control on the relative abundance and richness of reptiles and amphibians using drift fence arrays with pitfall and funnel traps. Three replicate blocks were established at the Green River Game Land, Polk County, North Carolina. Each replicate block contained four experimental units that were each approximately 14 ha in size. Treatments were prescribed burn (B); mechanical understory reduction (M); mechanical + burn (MB); and controls (C). Mechanical treatments were conducted in winter 2001–2002, and prescribed burns in March 2003. Hot fires in MB killed about 25% of the trees, increasing canopy openness relative to controls. Leaf litter depth was reduced in B and MB after burning, but increased in M due to the addition of dead leaves during understory felling. The pre-treatment trapping period was short (15 August–10 October 2001) but established a baseline for post-treatment comparison. Post-treatment (2002–2004), traps were open nearly continuously May–September. We captured a total of 1308 species of 13 amphibians, and 335 reptiles of 13 species. The relative abundance of total salamanders, common salamander species, and total amphibians was not changed by the fuel reduction treatments. Total frogs and toads (anurans) and Bufo americanus were most abundant in B and MB; however, the proximity of breeding sites likely affected our results. Total reptile abundance and Sceloporus undulatus abundance were highest in MB after burning, but differed significantly only from B. Mean lizard abundance in MB was highest in 2004 and higher than in other treatments, but differences were not statistically significant. Our results indicate that a single application of the fuel reduction methods studied will not negatively affect amphibian or reptile abundance or diversity in southern Appalachian upland hardwood forest. Our study further suggests that high-intensity burning with heavy tree-kill, as in MB, can be used as a management tool to increase reptile abundance – particularly lizards – with no negative impact on amphibians, at least in the short-term.     

火干扰对天然红松林结构和演替过程的影响

Investigations on charcoal in the soil, fire-scarred trees, stand composition, forest structure as well as regeneration status were carried out in the natural broad-leaved/Korean pine (Pinus koraiensis) forest after fire disturbance at Liangshui Nature Reserve on the mid-north of Xiaoxing‘an Mountains from 1990 to 1992, and the ecological effects of fire disturbance on the formation and succession of this kind of forest were analyzed according to the survey results. The average depth of charcoal in the soil was related to the timing of the fire. According to the characteristic of fire-scarred trees, the dynamic map of the fire behavior was drawn onto the topographic map. It showed that the dimension and extent of the fire disturbance was closely related with site conditions. Fire disturbance only led to a significant difference in stand composition and diameter class structurefor the stands at different locations, rather than completely destroying the forest. After fire disturbance, the horizontal community structure was a mosaic of different patches, which were made up of different deciduous species or different sizes of Korean pines, and the succession trend of each patch was also different. In the sites with the heavy fire disturbance, the intolerant hardwood species were dominant, and there were a large number of regenerative Korean pine saplings under the canopy. In the moderate -disturbed sites, the tolerant hardwood species were dominant, and a small number of large size Korean pines still survived. In the light-disturbed sites, large size Korean pines were dominant.     

森林航空消防在森林火灾扑救中的作用分析

森林航空消防是森林火灾扑救中不可替代的重要组分。通过分析森林航空消防在2017年和2018年春季发生在内蒙古自治区东部林区的森林火灾扑救中的具体应用,总结了现阶段限制森林航空消防优势发挥的主要因素,提出了我国森林航空消防应急能力提升的应对措施和建议。     

Long-term influence of fire and harvesting on boreal forest age structure and forest composition in eastern Québec

In boreal forests, historical variations in the area disturbed by natural disturbances or harvesting have rarely been compared. We measured temporal and spatial variations in areas affected by severe fires and clearcutting throughout the 20th century in a 57, 332 km² section of the eastern Canadian boreal forest. We examined the effects of these disturbances on spatio-temporal variations in the abundance of forests >60 years. Natural variability for the abundance of forests >60 years was estimated from simulations of natural disturbance regimes. We also measured compositional and structural differences between three categories of stands originating from relatively recent disturbances (∼50 years; clearcutting, fires, and clearcutting followed by fires), and one category of stands that were undisturbed for at least 200 years. At the regional level, we observed that forests >60 years gradually became scarcer throughout the 20th century due to a gradual expansion of harvested areas, an effect most pronounced in the southern part of the region, where mature and old forest abundance was clearly outside the range of natural variability at the end of the studied period. At the stand level, forest composition and structure differed between stand-origin categories: clearcutting-origin stands contained more balsam fir (Abies balsamea), fire-origin stands more black spruce (Picea mariana), and fire/clearcutting-origin stands more hardwoods (Betula papyrifera and Populus tremuloides). Overall, we estimate that strict forest management targets based on natural disturbance regimes will be difficult to achieve in eastern North-American boreal forests, most notably because contemporary disturbance rates, including both clearcutting and fire, have gradually become higher than the fire rates observed during the preindustrial period.     

Survival to prescribed fire of plantation-grown Corsican black pine in northern Portugal

Context

The current fire regime threatens black pine (Pinus nigra Arn.) persistence in the Mediterranean Basin, which recommends larger-scale fuel treatments. Prescribed burning is an option for stand protection but its use in young stands (which are particularly at risk) is hindered by the scarce knowledge on post-fire tree survival.

Aims

The objectives were to characterize bark thickness as a fire-resistance trait in P. nigra and to describe how post-fire tree survival responds to tree size and fire effects in a 16-year-old plantation.

Methods

Bark thickness was related to diameter at breast height and height in the stem. Metrics describing tree size and stem and crown damage were measured 1?year after prescribed burning in 259 trees. Tree survival was modeled with logistic regression and Classification and Regression Tree analysis.

Results

Bark thickness increased linearly with diameter at breast height (dbh) and decreased with height in the stem. Tree survival was primarily a function of crown injury. Stem damage was an influent factor in small trees.

Conclusion

Due to thinner bark and lower tolerance to crown damage, young P. nigra trees are less fire-resistant than other Mediterranean pines, e.g., Pinus pinaster. Prescribed fire should not be attempted if dbh <10?cm. Mechanical clearing is the treatment of choice in young stands with a significant shrub layer.     

森林火灾现场指挥扑救与决策

近年来,森林火灾频频发生,对生态环境和生态安全构成了严重的威胁。面对频发的森林火灾,现行管理体制与经济体制不相适应,严重缺乏公众参与,未能建立起协调有效的森林火灾现场指挥扑救决策预案等。因此,必须开展森林火灾现场指挥扑救决策研究,更新管理模式,创新管理体制,建设管理体系,及时有效地扑灭森林火灾,从而促进森林生态安全和森林可持续发展。     

扑救跳石塘林火的方法及体会

跳石塘(俗称哈砬子)系火山爆发经喷射燃烧玄武岩石块堆积而成。塘内石块相互搭接,漏孔较大,呈条状或块状分布,凹凸不平,周边常与塔头草甸相连,林分多为阔叶林。2002年9月27日,辉南县大椅山林场57林班,因一村民野外生活用火引起山火。整个火场地貌均为跳石塘。现将组织扑救过程中一些做法和体会做一总结,旨在与各位同仁商榷提高。1跳石塘林火特点1.1可燃物干燥、厚度较大跳石塘地表可燃物多为天然林枯枝落叶,积累时间长,年代久远,造成厚度较大,缺水干燥,一遇火源,极易燃烧。1.2隐蔽性强跳石塘内漏孔多,地表燃烧后,火源即漏入石缝下,形成地下…