69．Growing tightly packed together and collectively weaving a densecanopy of branches, a stand of red alder trees can totally dominate a site tothe exclusion of almost everything else.

(特殊结构to the exclusion of 除…的存在)

一片红赤杨树紧紧长在一起，枝叶共同编织出一个厚密的树顶，它们能够完全占领一个地方，以致排除几乎任何其他东西的生长。

分句1. Growingtightly packed together and collectively weaving a dense canopy of branches

分句2. a standof red alder trees can totally dominate a site to the exclusion of almosteverything else.

1和2嵌套

1是现在分词独立成分，做句子的状语。