2019年6月浙江卷 C
California has lost half its big trees since the 1930s, according to a study to be published Tuesday and climate change seems to be a major factor (因素).
The number of trees larger than two feet across has declined by 50 percent on more than 46,000 square miles of California forests, the new study finds. No area was spared or unaffected, from the foggy northern coast to the Sierra Nevada Mountains to the San Gabriels above Los Angeles. In the Sierra high country, the number of big trees has fallen by more 55 percent; in parts of southern California the decline was nearly 75 percent.
Many factors contributed to the decline, said Patrick McIntyre, an ecologist who was the lead author of the study. Woodcutters targeted big trees. Housing development pushed into the woods. Aggressive wildfire control has left California forests crowded with small trees that compete with big trees for resources (资源).
But in comparing a study of California forests done in the 1920s and 1930s with another one between 2001 and 2010, McIntyre and his colleagues documented a widespread death of big trees that was evident even in wildlands protected from woodcutting or development.
The loss of big trees was greatest in areas where trees had suffered the greatest water shortage. The researchers figured out water stress with a computer model that calculated how much water trees were getting in comparison with how much they needed, taking into account such things as rainfall, air temperature, dampness of soil, and the timing of snowmelt (融雪).
Since the 1930s, McIntyre said, the biggest factors driving up water stress in the state have been rising temperatures, which cause trees to lose more water to the air, and earlier snowmelt, which reduces the water supply available to trees during the dry season.
27.What is the second paragraph mainly about?
A. The seriousness of big-tree loss in CaliforniaB. The increasing variety of California big trees.
C. The distribution of big trees in California forests.
D. The influence of farming on big trees in California
28.Which of the following is well-intentioned but may be bad for big trees?
A. Ecological studies of forests. B. Banning woodcutting.
C. Limiting housing development. D. Fire control measures.
29.What is a major cause of the water shortage according to McIntyre?
A. Inadequate snowmelt. B. A longer dry season
C. A warmer climate D. Dampness of the air
30.What can be a suitable title for the text?
A. California's Forests: Where Have All the Big Trees Gone?
B. Cutting of Big Trees to Be Prohibited in California Soon
C. Why Are the Big Trees important to California Forests?
D. Patrick McIntyre: Grow More Big Trees in California
答案：
27. A
28. D
29. C
30. A
答案解析：
根据第二段中详细列举的加利福尼亚不同地区大树数量下降的具体数据，如“the number of big trees has fallen by more 55 percent; in parts of southern California the decline was nearly 75 percent”可知，该段主要是在说明加利福尼亚大树损失的严重性，所以选A。
根据“Aggressive wildfire control has left California forests crowded with small trees that compete with big trees for resources (资源).”可知，积极的野火控制措施本是好意，但却导致小树与大树争夺资源，对大树不利，所以选D。
根据“Since the 1930s, McIntyre said, the biggest factors driving up water stress in the state have been rising temperatures...”可知，气温上升(气候变暖)是导致缺水的主要原因，所以选C。
文章主要围绕加利福尼亚自20世纪30年代以来失去了一半的大树这一现象展开，阐述了导致大树减少的因素等，A选项“加利福尼亚的森林：那些大树都去哪儿了?”符合文章主旨，所以选A。
