图1 通过传统的地面监测拍摄的展叶图片(Richard B. Primack摄于美国Massachusetts州波士顿阿诺德植物园)

Fig. 1 Leaf out pictures taken by scientists monitoring leafing in a traditional on-the-ground study (taken by Richard B. Primack at the Arnold Arboretum in Boston, Massachusetts USA)

图2 通过卫星数据拟合的美国东北部新英格兰地区的森林冠层生长过程。植被数据根据逻辑斯蒂S型增长函数来拟合, 植被绿色的开始和消退时间通过回归曲线的半最大值获得。数据点的误差大小通过符号的深浅来指示, 黑色菱形表示误差最小, 白色菱形表示误差最大(图来源于Fisher et al., 2006)。

Fig. 2 A graph showing the growth of the leaf canopy over a growing seasons using satellite data from a location in New England, in the northeastern United States. The vegetation data is fit to logistic growth sigmoid functions and the onset and offset of greenness are calculated at the half-maxima of the curve. The quality of the data points is indicated by the symbol shading, with black diamonds having the least error and white diamonds having the most error. Figure from Fisher et al., 2006).

图3 2011年春天, Massachusetts州康科德地区民兵导弹国家历史遗址公园的林冠层在3周中的变化(Richard Primack摄)

Fig. 3 A sequence of photos taken over a three week period in the spring of 2011 showing the development of the leaf canopy at Minute Man National Historical Site, a park in Concord, Massachusetts (Photos by Richard B. Primack)

图4 温暖期过后的霜冻天气对美国东北部一个山坡的林冠层造成了损害。对温暖天气响应快速的树种如糖枫, 展叶提早, 叶片遭受损害, 而展叶相对保守的物种, 比如美国山毛榉, 生长正常(图片来源于Hufkens et al., 2012b)。

Fig. 4 A hillside in the northeastern United States showing the effects of a late frost following a period of warming. Trees that responded more quickly to warm temperatures, such as sugar maples, suffered damage to early leaves, while more conservative leafing species, such as American beech, fared better and are developing normally. Figure from (Hufkens et al., 2012b).

Fig. 5 Leaf out pictures taken at the Arnold Arboretum in Boston, Massachusetts USA by scientists monitoring leafing in a traditional on-the-ground study (taken by Dr. Richard B. Primack)

Fig. 6 A graph showing the growth of the leaf canopy over a growing season using satellite data from a location in New England, in the northeastern United States. The vegetation data is fit to logistic growth sigmoid functions and the onset and offset of greenness are calculated at the half-maxima of the curve. The quality of the data points is indicated by the symbol shading, with black diamonds having the least error and white diamonds having the most error (Figure from Fisher et al., 2006).

Fig. 7 A sequence of photos taken over a three week period in the spring of 2011 showing the development of the leaf canopy at Minute Man National Historical Site, a park in Concord, Massachusetts, with a bridge, a monument, and statue as points of reference. The leaf out times of individual trees can be seen in these photos. Photos by Richard B. Primack.

Fig. 8 A hillside in the northeastern United States showing the effects of a late frost following a period of warming. Trees that responded more quickly to warm temperatures, such as sugar maples, suffered damage to early leaves, while more conservative leafing species, such as American beech, fared better and are developing normally. Figure from (Hufkens et al., 2012b)