Characteristics of snags containing excavated cavities in northern Arizona mixed-conifer and ponderosa pine forests
Characteristics of snags containing excavated cavities in northern Arizona mixed-conifer and ponderosa pine forests
复制标题
亚利桑那州北部混合针叶树和黄松林中含有挖掘空洞的障碍物的特征
DOI：
10.1016/j.foreco.2004.05.042
复制
发表时间：
2004
影响因子：
3.7
通讯作者：
Scott C. Vojta
中科院分区：
文献类型：
--
作者：
J. Ganey;Scott C. Vojta
障碍为美国西南部大量的洞巢鸟类提供了重要的资源。为了扩大我们对该地区洞穴筑巢鸟类利用洞穴的了解，我们记录了针叶和黄皮松混交林中有洞穴和没有洞穴的洞穴的特征。(不含法律)亚利桑那州中北部的森林。在横跨两个国家森林的占地约73,000公顷的研究区域内，随机抽取了113个方块(每块1公顷)的陷阱进行抽样。针叶混交林(n=53个样地)的空隙密度是黄松林(n=60个样地)的3倍，但不同森林类型的空隙密度和总空穴密度没有差异。在两种森林类型中，有孔洞的林木比没有孔洞的林木直径更大，保留的树皮更少。黄皮松和甘柏(Quercus Gambeli Nutt.)障碍，大多数是在顶部破碎的高级衰变课程中遇到的障碍。我们的结果与以前在黄松林的研究结果基本一致，但不同于以前的研究，这些研究记录了针叶混交林中空巢鸟大量使用颤杨(Pillius Tremuloides Michaux)。这些结果支持了管理，以保护和招募分布在整个景观上的大陷阱。在这两种森林类型中，黄皮松和甘贝尔栎树的使用相对较多，这表明应该强调对大的松树和橡树障碍的补充，以前的研究建议也强调杨树的补充。这可能需要在针叶混交林中进行特别管理。这些物种在这种森林类型中是相对不耐荫的系列物种，由于灭火努力和由此产生的生态演替模式，它们在这种森林类型中明显正在衰落。
Snags provide an important resource for a rich assemblage of cavity-nesting birds in the southwestern United States. To expand our knowledge of snag use by cavity-nesting birds in this region, we documented characteristics of snags with and without excavated cavities in mixed-conifer and ponderosa pine (Pinus ponderosa Dougl. ex Laws) forest in north-central Arizona. Snags were sampled in 113 square plots (1ha each) randomly located within a study area covering approximately 73,000ha across two National Forests. Density of snags was three times greater in mixed-conifer forest (n = 53 plots) than in ponderosa pine forest (n = 60 plots), but density of snags containing cavities and overall cavity density did not differ between forest types. In both forest types, snags containing cavities were larger in diameter and retained less bark cover than snags without cavities. Most cavities were in ponderosa pine and Gambel oak (Quercus gambelii Nutt.) snags, and most were in snags in advanced decay classes with broken tops. Our results are largely consistent with previous results from ponderosa pine forest, but differ from previous studies that documented heavy use of quaking aspen (Populus tremuloides Michaux) by cavity nesters in mixed-conifer forest. These results support management to protect and recruit large snags well distributed across the landscape. The relatively high use of ponderosa pine and Gambel oak snags in both forest types suggests that recruitment of large pine and oak snags should be emphasized, and previous studies suggest emphasizing aspen recruitment as well. This may require special management efforts in mixed-conifer forest. These species are relatively shade-intolerant seral species in this forest type, and are apparently declining in this forest type due to fire-suppression efforts and resultant patterns of ecological succession.