【作者】 徐嘉；

【导师】 费世民； 胡庭兴；

【作者基本信息】 四川农业大学 ， 森林培育， 2008， 硕士

【摘要】 云南松(Pinus yunnanensis)系川西南山地主要针叶森林类型的优势树种,也是川西南偏干性常绿阔叶林的先锋树种和用材树种之一。目前,关于云南松林经营的研究有很多,但关于云南松林窗特征及林窗更新情况的报道较少。而林窗作为最为常见的一种干扰,并且是森林自我更新的重要途径之一。开展林窗更新的研究,将有助于科学评价云南松林的更新能力、林窗干扰状况和森林演替发生规律,探讨云南松林和偏干性常绿阔叶林更新、维持和循环动态,具有很强的实际意义。本文以四川省攀枝花市大黑山森林公园云南松林为对象,研究了川西南山地云南松林林窗的一般特征,并对云南松林窗下更新做了详细的研究,以期为云南松林经营及川西南山地植被恢复提供科学依据。研究结果表明:(1)云南松林窗形状呈椭圆形,CG的长短轴比为1.8,EG的长短轴比为1.5。林窗大小:CG为255.6±195.7m~2(18.1-934.5m~2),EG为458.9±272m~2(50.7-1356.5m~2);以500m~2以下的林窗占主体。林窗形成木以1-5株占主体,主要死亡方式为风倒,枯立木和人工砍伐各占到25%左右,云南松林窗有七种形成方式:风倒、枯立、人工砍伐、风倒+枯立、风倒+人工砍伐、枯立+人工砍伐和风倒+枯立+人工砍伐。平均每个林窗拥有2.64株形成木,每个形成木可形成林冠林窗118m~2,扩展林窗219m~2。形成木的平均树高为17.6±2.8m(11.5-24.9m)、年龄为89.3±24.7a(15-140a)和胸径为35.6±7.5cm(18-64cm)。通过相关分析,林窗大小不受林窗形状的影响,但受形成木和边界木特征的影响。形成木和边界木越大,群落年龄越大,林窗的大小越大。在云南松林的可持续经营中,要合理利用形成木,并模拟自然干扰规律适时择伐、人工科学地促进森林循环。(2)云南松林林窗边界木主要组成树种为云南松,边界木为5～9株的林窗数量最多(74%);单个林窗边界木平均高度多数在18～22m之间(61%),平均胸径多数在35～50cm之间(82%);边界木偏冠现象明显,偏冠率1均大于0.5,单个林窗边界木偏冠率1平均值集中在0.6～0.8之间(75%);边界木的个体大小随林窗面积增大而增加。(3)云南松边界木偏冠现象普遍存在,树冠偏倚程度大于0.5的个体达到了95%[偏冠率一,0.72±0.14(0.231～1)]和93%[偏冠率二,0.86±0.37(0.134～2.583)]。在特定的自然地理条件下,云南松边界木偏冠方向和方位可能有关,树冠偏向南方的边界木近80%。偏冠率一和胸径、侧树间距、后树间距存在显著相关关系,和树高、枝下高无关;偏冠率二和侧树距离有关,和胸径、树高、枝下高、后树距离无显著相关关系。综合结果表明,云南松边界木偏冠程度受邻体树木分布和云南松自身特征的影响。(4)选用Weiner指数、Hegyi指数和张跃西指数计算竞争强度,研究了云南松老龄林径级相当的枯立木和活立木的邻体竞争强度。将8m范围内邻体分为三类:云南松、科斗科类和其它类,分别占42.83%、20.65%、36.52%(枯立木)和44.29%、22.49%、33.22%(活立木)。分别受枯立木和活立木周围邻体的分布格局差异的影响,邻体对云南松枯立木的种内竞争和种间竞争相当,对云南松活立木的竞争以种内竞争占优势。邻体对云南松枯立木的竞争强度小于活立木的,但不存在统计学上的显著差异。由于枯立木死亡后大小不变,三个指数所得枯立木竞争强度均大于枯立木死亡时的竞争强度。因此,活立木的竞争强度比枯立木死亡时受到的竞争强度还要大,这表明枯立木死亡受邻体竞争影响的可能性较低。由于Weiner指数、Hegyi指数和张跃西指数的构建参数不同,同样数据所得竞争强度各不相同,随距离的变化趋势也各异,但在计算云南松枯立木和活立木竞争强度时获得了一致结果。(5)林窗干扰有利于云南松更新,但不同的林窗大小、年龄、开阔度等林窗特征影响着川西南山地云南松的更新。云南松幼苗在小林窗中更新密度最大,而大林窗中云南松幼树、成树的密度较大。幼苗和幼树在幼年林窗中密度较大,而成树在老年林窗中密度最大。云南松幼苗密度随开阔度的提高而降低,幼树和成树的密度则增加。开阔度越大云南松个体也越大,但在开阔度低于0.6的林窗中,云南松不能更新。在小林窗、幼年林窗以及开阔度在0.6～1.0的林窗中,云南松幼苗向幼树的转化率较低。林窗和非林窗下云南松的重要值均排第一位,表明未来该研究区域森林仍以云南松为主。更多还原

【Abstract】 Pinus yunnanensis, one of dominant species in In the mountainous area of southwestern Sichuan province, is a pioneer species and timber tree for quasi-wet broad-leaved forest. Current studies about Pinus yunnanensis mainly focus on the forest management, and little on the relation of gap characters and Pinus yunnanensis regeneration in the Pinus yunnanensis forest. Study on gap regeneration is benefit for us to realize the process of Pinus yunnanensis forest cycle and evaluate the capability of nature Pinus yunnanens forest in regeneration and sustaining. Therefore, the gap characteristics of Pinus yunnanensis forest gap and its regeneration, in Dahei mountain forest park, panzhihua city, Sichuan province, were studied. The factors influencing gap regeneration were further analyzed. Result were as follows:(1) There was an ellipse shape in gap and the proportion of long and short axes was 1.8 in the canopy gap (CG) and 1.5 in the expand gap (EG). Gap area was mainly below 500m2, and averaged as 255.6±195.7 m~2 ranging from 18.1 to 934.5 m~2 in CG, and as 458.9±272 m~2 from 50.7 to 1356.5 m~2 in EG. Gap size depended on the community environments before the gap formation, and the taller, bigger and more numerous gap boundary trees and gap makers produced bigger gaps. There was averagely 2.64 gap makers in each gap (from 1 to 10, and 8 was in short), and half of the gap maker came from wind treefall, 1/4 from standing death and artificial cutting respectively. On the basis of field survey, there were seven gap formation modes: wind treefall (WT), standing death (SD), artificial cutting (AC), WT, WT+ AC, SD+ AC and WT+ AC + SD, and each gap maker could produce 118 m2 CG and 219 m2 EG. The features of gap makers showed as follows: 17.6±2.8 m (averagely and from 11.5 to 24.9 m)in height, 89.3±24.7 a(from 15 to 140 a)in age, and 35.6±7.5cm(from 18 to 64 cm) in DBH. Through the coefficient analysis, we found that gap size did not affected by gap shape, but affected by the characteristics of gap makers and border trees. There were bigger gap makers and border trees, the older community age, and the larger gap size in Pinus yunnanensis forest. On the account of the sustainable management for forests, we should use the gap maker with reason, and selectively and corporately cut the timber, cultivate and manage natural forests according to the rules of nature disturbance for Pinus yunnanensis forest.(2) In Pinus yunnanensis forest, the most GBTs were Pinus yunnanensis and there were mainly 5～9 GBTs per gap (75%);The average height of GBTs per gap was mainly form 18 to 22m (61 %), and the average diameter at breast height was mainly form 35 to 50 cm (82%); The GBTs’ crow inclination are obvious, and RCI-1 was greater than 0.5, the average RCI-1 of GBTs per gap was mainly form 0.6 to 0.8 (75 %); The size of GBTs increased with the area of gaps.(3) Crown inclination is consequences that the biological and its environmental factor synthetically influence the crown structure. In the border trees of Pinus yunnanensis gaps in the mountain area of southwest Sichuan, the crown inclination phenomenon, and whether the distribution of neighborhood trees influenced the degree of crown inclination were investigated in this paper. The crown inclination phenomenon was a general feature in the border tree of Pinus yunnanensis, the individual amounts of degree of crown inclination bigger than 0.5 reached 95% [crown inclination 1 (shorted as RCI-1), averaged as 0.72±0.14 (n=291,0.231～1 )]and 93%[RCI-2, averaged as 0.86±0.37(n=291, 0.134～2.583)]. In the especially location studied, the orientation of crow inclination probably related to azimuth, and there were near 80% border trees that were west orientation including southwest and northwest. The RCI-1 significantly related to DBH, lateral tree intervals, back tree intervals, but not to height and low branch height of border trees; the RCI-2 was only obviously correlated with lateral tree intervals, not with DBH, height, low branch height, back tree intervals. Summarily, distribution of neighborhood tree mainly influenced the degree of crown inclination, and probably its size as well in the border trees of Pinus yunnanensis gaps.(4) Three competition indices were used to analyze the neighborhood competition between the standing death tree and living tree, which are in the same DBH. Compartmentalize neighborhood around objective tree in 8m into three types: Pinus yunnanensis、Fagaceaea and other trees. The result shows that, around standing death tree, Pinus yunnanensis、Fagaceaea and other trees individual numbers account different for 42.83 %, 20.65 % and 36.52 % of all individual numbers. Around living tree. Pinus yunnanensis, Fagaceaea and other trees individual numbers account different for 44.29%、22.49% and 33.22% of all individual numbers. For standing death tree, Intra-specific competition and Inter-specific competition are similitude (p>0.05). For living tree, Intra-specific competition> Inter-specific competition(p<0.05) . The competition effects for standing death tree is larger than that for living tree, but the diversity of them is not marked (p>0.05) .Meanwhile, the size of standing death tree have stop growing, but the growth of Neighborhood will release. So, the competition indices, when the tree died, would be lower than which we account. Base on the two points, competitive effect leading standing death tree up to die is not fact. Weiner index、Hegyi index and Zhang Yuexi index are different model, but the results are accord when using the three competitive index for analyzing the neighborhood competition between the standing death tree and living tree.(5) By analyzing effects of gap properties, including gap size, gap age, canopy openness, on the regeneration of Pinus yunnanensis forests in the mountainous area of southwestern Sichuan, the characteristics of regeneration in gap of P. yunnanensis forests were approached. The results showed as follows: 1) there was a higher density of seedlings in smaller gaps, but a higher density of saplings and mature trees in large gaps; 2) there was a higher density of seedlings and saplings in young gaps, and a higher densities of mature trees in mature gaps; 3) with the increasing of canopy openness, density of seedlings decreased, but density of saplings and mature trees increased, and until canopy openness was lower than 0.6, there was no regeneration in gap of P.yunnanensis forests; 4) the transition rate of seedlings to saplings was lower in small gap, young gap and 0.4-0.6 of canopy openness. 5) the importance value of P. yunnanensis listed the first both in gaps and non-gap, indicating the forest in this area will be mainly composed with P. yunnanensis in the future.更多还原