Upper and lower treelines are particularly exposed to a changing climate. It has been hypothesized that upper treelines are constrained by growing season temperature, whereas lower tree lines are water limited. We expect different causal mechanisms of upper versus lower tree line formation to generate distinct patterns of spatial heterogeneity. Here, we compare dynamics, spatial patterns and shape complexity of upper and lower tree lines of semi‐arid pinyon‐juniper woodlands.

中文翻译：

---

半干旱松柏林地上，下林线生物地理格局

上下林线特别容易受到气候变化的影响。据推测，较高的树线受生长季节温度的限制，而较低的树线受水的限制。我们期望上层树线和下层树线形成的不同因果机制产生不同的空间异质性模式。在这里，我们比较了半干旱Pinyon-Juniper林地的上，下树线的动力学，空间格局和形状复杂性。