[揽瓜阁精读] 88.树的年轮

lanreach_001

看一下

dreamsista

看看

筱雅Jane510

看一下！               

秋桂红

同意！               

筱雅Jane510

88

[Main Idea] Scientists have found that some tropical trees have invisible age rings, and the calcium method is quicker than the common carbon isotope measurements. But there still are many problems have not been solved. Scientists need cooperation and further study.

[Structure]

P1: Research background and problem (only a few type of tropical trees have visible rings which can show their age).

        P2: The common measurements (oxygen and carbon isotopes) and PP’s new point of view (tropical trees have invisible rings).

        P3: PP’s new method (two methods got similar results, but calcium method is much quicker).

        P4: Problems (whether seasonal calcium cycles are common) and scientists need cooperation (PP&ATRIC)

P5: Need further study to understand better of tropical forest dynamics.

taylor_2008

同意！               

JourneyC

看一下！               

在水里睡觉

同意！               

chishua

P1 数年轮（反映了季节的变化）就能看树龄。但热带树不行，但现在已经有一种简单的方法。但只有少数树有可见的年轮：季节之间差异太小，无法留下明显的标记。
P2 原先依靠对氧和碳同位素的测量来确定年龄，但PP&同事已经证明，看不到年轮的树确实有年轮。
P3 钙和碳同位素测量结果一致（可以追溯到1909年的年度峰值），但更快，只要一个下午
P4 研究者不知道这个特点是共同的还是特有的；也不清楚干旱期是否会让这一信号不能解码。P将会跟STGI 中心（一个持续监管森林很久的机构）继续合作
P5 热带系统依旧是神秘的，任何测量手段都能为研究热带雨林动态系统作贡献。

wannatechan

Mark一下！