Читать книгу The Trees of San Francisco онлайн

30 страница из 42

The tree was introduced into southern Florida in the early 1900s for swamp drying. Having no natural enemies, it spread aggressively, crowding out the native vegetation that is essential for supporting animal life. Now, the cajeput poses a serious environmental threat to the Everglades and other expanses of southern Florida, where it is growing explosively, turning the natural grassy wetlands into dense melaleuca thickets. Biological control is now offering hope, however. The U.S. Department of Agriculture is releasing several species of Australian snout beetles, which are specific to melaleuca and feed on its shoots, reducing the plant’s ability to reproduce.

Aesculus californica

CALIFORNIA BUCKEYE

LOCATION: 2694 McAllister St./Willard St. N. near the University of San Francisco campus; also at 124 Lower Terrace/Levant St. in the Upper Market neighborhood

This is one of the few trees in this book that is a true San Francisco native, existing within the current city limits before the arrival of Europeans. The California buckeye also is one of the state’s most beautiful native trees, growing to 20 feet in height on wind-protected sites in the dry slopes and canyons of the coastal range and Sierra foothills. The tree produces showy, long-lasting clusters of white flowers in May and June. One or two pear-shaped fruits form on each flower cluster, and inside each fruit’s leathery jacket is a seed with a shiny brown coat. The tree’s light green leaves are divided into five to seven leaflets, which drop in July (an adaptation to long, dry summers) unless summer water is provided.