Moderate shaking of Liquidambar trunks for 30 seconds daily reduced height growth to only 20 to 30 percent of that of trees not shaken. Six of eight trees shaken set terminal buds within 3 weeks. The trees which were not shaken formed no terminal buds. An endogenous mechanism for regulating tree growth in windy situations is implicated.
and second, there is a twofold difference We do not feel that we have confounded age with location in our studies. As we said, "we studied two adjacent abandoned hayfields," and "macroclimate and soil series are identical." Both fields were planted in timothy (Phleum pratense) and are slowly decaying into "natural" ecosystems characteristic of upstate New York. Since timothy is hardly a species characteristic of impoverished sites (1), we assume that whatever impoverishment leads to invasion of Poa compresa and Hieraciuim pratense arises out of the successional aging process. We have extensive soil data on the two fields as well as a description of their previous land usage from the land's owner. These data could not be included in a report in Science.
Trunk development of young container-grown trees was influenced by pruning and staking practices. The conventional nursery practice of staking and severely pruning laterals of container-grown trees produces plants which usually cannot stand without support when planted in the landscape. However trees were produced that were able to stand erect without staking by eliminating stakes during production, leaving lateral branches on the trunk, and spacing plants so their tops were free to move. Even though rigidly staked trees with lower limbs removed grew taller, they developed less caliper at the trunk base, much less taper to the trunk, and a smaller root system. Most of the trees staked during production, regardless of whether they were lightly or severely pruned, were not able to stand upright when planted out, while the unstaked trees needed no support.
The spacing of container-grown Betula verrucosa Ehrh., Eucalyptus sideroxylon A. Cunn., Dodonaea viscosa ‘Purpurea’ Jacq., and Liquidambar styraciflua L. was studied at 2 California locations in 1967 and 1968. As area per plant increased from can-to-can spacing, trunk caliper and taper increased, as did wt of roots and branches plus leaves, but increases in height and wt of trunk were less. At the closest spacings, the lower foliage was sparse, giving the trees a leggy appearance. Adequate spacing, about twice the can-to-can area, the first season gave benefits of increased trunk caliper and fuller foliage with a minimum sacrifice in height.
Kenya is one of the more than 50 nations constituting the vast continent of Africa. Richly diverse, culturally and geographically, Kenya lies astride the equator in East Africa, in the same time zone as Moscow and Iraq. Kenya's size (5.8 × 10 5 km 2 ) equals that of Wisconsin, Minnesota, Iowa, and Indiana combined. The Indian Ocean forms the eastern coast of Kenya, from which the land gradually rises westward into the upland plains of 900-to 1800-m elevation and mountain ranges >2700 m (Fig. 1). In the southern portions of the upland plains, annual precipitation averages ≈500 mm. TO the north and east, generally <250 mm of rain falls annually, rendering that area (≈60% of Kenya's total area) unsuitable for nonirrigated agriculture.The Great Rift Valley, averaging ≈32 to 56 km wide and part of a 5600-km-long geological formation along rift faults in Africa's tectonic plate, bisects Kenya along its northsouth axis. Large mountain ranges and plateaus are found on both sides of the Rift Valley, many >2500 m elevation. During the coldest months (July-August), radiation/valley frosts occasionally occur at elevations >2500 m, damaging frost-sensitive crops. East of the Rift Valley is Mount Kenya; hence, the name of the country. Mount Kenya, at 5199 m, is the second highest mountain in Africa and the world's largest shield-type volcano. The mountain is centrally located in the country and can be seen from as far away as 100 km. Even though it is almost directly on the equator, perennial snow and ice can be found above 4500 m. Permanent streams flowing off the mountain are a vital source of water to millions of people. On the southern border of Kenya is Mount Kilimanjaro (5895 m), Africa's high-
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