Assessing the situation of non-forest private woodlands: The Turkish case

This paper examines the situation of private woodlands in Turkey, which are referred to as ‘non-forest private woodlands’ (NFPWs). The questions addressed by this study are ‘Why are NFPWs not defined as forest?’, ‘Is the exclusion of NFPWs from forests reasonable?’ and ‘What are the consequences of excluding NFPWs from the forest regime?’. It is found that the criteria used to define a forest in Turkey, and hence to exclude NFPWs from forests, do not have a rational basis. Moreover, the threshold level of area, the most decisive criterion, is far beyond comparable international values and cannot be explained by country peculiarities. Also, NFPWs are more likely to be granted tree cutting approval if they have some type of official cadastre or if they harvest trees for domestic use. Commercial-use NFPWs make tree cuttings in higher quantities than domestic harvesters. NFPWs in general can be perceived as fuelwood harvesters as opposed to industrial wood suppliers. NFPWs with forest or land cadastre tend to harvest at higher levels compared to those without a cadastral survey. In the 8-year period 1993 and 2000, approximately 2.5 M m³ of wood was harvested on NFPWs across Turkey. The annual wood production on NFPWs throughout the country decreased drastically during that period, from about 700,000 m³ down to about 150,000 m³. This may be an alarming sign for environmental and socio-economic sustainability involving these lands. Forest management of these lands can be improved if the forestry administration authority implements planned environment-related regulative criteria as well as sound channels of communication, designed to lead the landowners towards best ‘forest’ management practices and hence to guarantee the sustainability of the communities and the natural resource base of the country.     

Fusarium pseudograminearum as an emerging pathogen of crown rot of wheat in eastern China

Fusarium crown rot of wheat has been spreading in the Huanghuai wheat-growing area in China since 2010, leading to a potential yield loss. To investigate the pathogens associated with this disease in Jiangsu and Shandong provinces in recent years, 617 Fusarium isolates were isolated from nine sites in these two provinces between 2014 and 2016. Of these isolates, 372 were identified as Fusarium pseudograminearum, and the remaining isolates were identified as F. asiaticum and F. graminearum, suggesting that F. pseudograminearum is becoming a predominant causative pathogen of crown rot of wheat in eastern China. Trichothecene gene detection and chemical analyses of trichothecenes indicated that the F. pseudograminearum isolates belonged to the 3-ADON or 15-ADON chemotype, and one isolate had the NIV genotype but produced no detectable NIV. 3-ADON isolates were predominant in Jiangsu, whereas 15-ADON isolates were prevalent in Shandong. The mating type of the F. pseudograminearum isolates were identified. MAT-1 and MAT-2 existed, but in most collections, particularly those in Jiangsu, the ratios of the two mating types deviated significantly from an expected 1:1 ratio. The reason for the occurrence of F. pseudograminearum is hypothesized, and the chemotype and mating type distribution of this species in these two provinces are analysed.     

小麦苗期浸种和根灌浅黄隐球酵母菌的定殖特征及对茎基腐病的防治效果

基于平板混合培养试验和浸种、根灌浅黄隐球酵母菌(Papiliotrema flavescens)温室盆栽试验,研究其在小麦苗期的定殖特征及对茎基腐病的防治效果。结果表明:1)在平板混合试验中,浅黄隐球酵母菌对禾谷镰刀菌的抑菌效果显著,抑菌率达84.1%;2)盆栽试验中,浅黄隐球酵母菌的定殖数量随时间推移呈减少趋势,浸种和灌根处理定殖数量均表现为叶鞘叶。与浅黄隐球酵母菌浸种处理相比,根灌浅黄隐球酵母菌处理的叶鞘浅黄隐球酵母菌定殖数量显著增加,并在接种后14d达到最大;3)盆栽试验中,根灌浅黄隐球酵母菌对禾谷镰刀菌的相对防效为22.7%,对假禾谷镰刀菌的相对防效为25.3%,均显著高于根灌生理盐水处理(P0.05),对小麦株高无影响。本研究表明通过根灌浅黄隐球酵母菌可以在小麦苗期实现定殖,并且对小麦苗期茎基腐病有一定防效。     

温度对假禾谷镰刀菌生长、侵染及茎基腐病发生的影响

研究温度对小麦茎基腐病发生的影响,可为病害的发生规律和生态防控措施的研究提供依据。本研究测定了温度对假禾谷镰刀菌菌丝生长、孢子萌发、对寄主小麦侵染以及在植株体内扩展的影响,结果表明,假禾谷镰刀菌菌丝生长的温度范围为4℃～30℃,其中28℃最适于菌丝的生长,孢子萌发的温度范围为4℃～35℃,其中12℃～30℃较适宜分生孢子萌发,17℃～28℃为假禾谷镰刀菌侵染小麦的适宜温度范围,假禾谷镰刀菌在小麦植株体内扩展的适宜温度范围在22℃～30℃;通过不同温度培养试验以及田间小麦不同生育期接种试验测定温度对小麦茎基腐病发生的影响,结果表明,播种期、起身期接种的小麦茎基腐病发生高于越冬苗期接种处理,而此期的温度较越冬苗期利于假禾谷镰刀菌的侵染和小麦茎基腐病的发生。     

采用水平集方法的无人机可见光DOM树冠分割

在天然林、混交林、复层林等复杂林分条件下,可见光森林影像受林分郁闭度、冠层结构、摄影季节等影响较大,对其进行树冠提取时,现有方法无法保证精度且缺乏有效的人工介入机制。该研究探索了一种能够在低郁闭度时自动分割,高郁闭度时可适当人工介入的树冠分割方法。先将无人机可见光森林影像处理成数字地表模型（Digital Surface Model,DSM）、数字高程模型（Digital Elevation Model,DEM）和数字正射影像图（Digital Orthophoto Map,DOM）,DSM与DEM相减得到树冠高模型（Canopy Height Model,CHM）,利用局部最大值法从CHM提取树顶点的平面位置生成泰森多边形,并以其外接矩形为基础生成树冠范围矩形,遍历并切分出单株立木树冠范围影像,进行各向异性扩散滤波后,通过水平集方法演化出树冠边界曲线。利用C#语言在ArcGIS Engine上实现基于水平集模型的可嵌入ArcMap运行的树冠分割插件。利用该插件对选自内蒙古大兴安岭大杨树林业局乃木河林场的不同郁闭度、不同树种组成的9块50 m×50 m天然混交林标准地的DOM影像进行树冠提取试验,同时与手工提取法和SVM图像分割法进行对比分析。结果表明本文方法的提取速度比手工提取法平均提高了45.97%;提取精度比SVM图像分割法平均提高了15.29个百分点。该方法在郁闭度低冠幅大时强调效率,在郁闭度高冠幅小时保证精度,是一种可伸缩性和通用性强的方法。     

格氏栲天然林林窗边界木特征研究

对格氏栲天然林林窗边界木的树种组成、胸径结构、高度结构和偏冠率进行了研究。结果表明:格氏栲天然林林窗边界木主要组成树种为格氏栲,所占比例为74.75%;林窗边界木胸径结构为尖峰呈左偏,符合正态分布、Weibull分布和β分布;边界木高度级结构呈正态分布,主要集中在15-30 m;林窗边界木存在明显的偏冠现象,仅有5.05%未出现偏冠现象,边界木的偏冠率主要在0.5-0.8之间(70.71%),不同树种间的偏冠率没有显著差异。林窗边界木大部分由发育良好的中、高径级树木组成,与林下相比林窗边界木大部分已过熟,仅存较少小径级的边界木,表明依靠林窗边界木完成林窗更新存在困难,需加强对林窗幼苗和幼树的保护,实现林窗更新。     

太行山侧柏人工林林冠降雨截留及地表径流的研究

对侧柏人工林分的林冠降雨截留及地表径流进行观测，要冠降雨截留量与降雨量相关，截留量随降雨量的增加而增加，截留率则相反，年截留率３３％；地表径流量和土壤侵蚀量与降雨量正相关，年地表径流量和土壤侵蚀量分别为３９．５ｍｍ和１３２７ｋｇ／ｍｈ＾２。     

华北落叶松天然林林冠层变化规律的研究

对林冠层的垂直变化的研究表明,树高Ｈ与天然整枝高度Ｌ相关极紧密,两因子增速比为１０：７。林冠层水平变化表现在冠径ｄ与胸径Ｄ、冠径ｄ和树高Ｈ相关均紧密,它们的增速比Ｄ／ｄ为１：１８．５、Ｈ／ｄ为４：１。林龄Ａ与冠径ｄ相关也很紧密,在同龄下,ｄ增宽速度Ⅰ地位级大于Ⅱ地位级,二者增速差距随林龄增大而加大。ｄ／ｌ与ｌ／Ｈ相关极紧密为近似直线的二次抛物线反相关类型,１０～３０年冠形变化较大,其变化速度Ⅰ地位级比Ⅱ地位级快５年,以上各相关规律可为间伐、修枝等抚育措施提出数量依据。     

我国河南和甘肃地区梨树根癌病病原菌鉴定

近年来, 我国梨树根癌病多有发生, 危害严重, 但病原尚不明确?本研究采集了河南商丘和甘肃庆阳梨树根瘤, 共分离得到13个分离物, 对其进行形态特征观察?序列分析和特异性PCR检测?生理生化测定和致病性测定?结果表明, 这13个分离物在NA平板上的菌落呈白色?圆形, 单菌落中间凸起?边缘整齐?它们均能在New Kerr培养基上良好生长?其16S rRNA基因序列与GenBank中已登录的Agrobacterium tumefaciens和A.rhizogenes序列相似性大于98%?将分离物人工接种向日葵后能使接种部位产生癌瘤?鉴定结果表明, 梨树根瘤中分离出的13个分离物均为生物Ⅱ型土壤杆菌?