100 UNIVERSITY OF CALIFORNIA EXPERIMENT STATION. 



have greatly aided it. Young trees planted out in the winter of 1901 

 and the present season have also done very well indeed. 



Drought- Resistance. All observations at the substation confirm the 

 view that on the light, gravelly wash of the mesa, the large tanbark 

 acacias stand the drought somewhat better than do the eucalypts. Seed- 

 ling trees also frequently spring up in the grove. With good' cultivation, 

 a grove of A. decurrens or A. mollissima can be established in such soil 

 without any irrigation and with an annual rainfall of only 10 inches. 



The largest specimen of A. decurrens, now twelve years old, girths 

 3 feet 9 inches, measured breast-high; this surpasses both A. mollissima 

 (largest tree, 2 feet 10 inches) and A. dealbata (largest tree, 2 feet 4 

 inches). A. cyanophylla, a low, shrub-like, much-branched tree, quite 

 unlike the two preceding species, which rise to 40 and 50 feet, has in 

 the case of the largest specimen a trunk girthing 3 feet 1 inch. All these 

 stand on soil similar to that of the older eucalypts and have suffered 

 less in times of drought. 



Acacia melanoxylon,, whose beautiful rosewood-like timber only needs 

 to be better known to be demanded among cabinet-makers, has now, 

 in 1902, fully recovered from its severe suffering in the years of 

 drought, when one half of the large trees of this species ceased growth 

 and some died. This recovery when the annual rainfall rose from 

 about 6 inches to nearly 12 inches is interesting, but the profitable 

 growth of this riverine species for timber is evidently limited to regions 

 of more rainfall and better soil. Nevertheless, the largest standing tree 

 of A. melanoxylon, aged twelve years, girths 3 feet 8 inches. 



The rapidity of growth of A. melanoxylon is hardly surpassed by any 

 other species, and it reproduces itself freely from root-cuttings or suck- 

 ers as well as from seeds. One large tree removed in 1899, because it 

 died in the ground, threw up a multitude of suckers scattered over a 

 large area. Nine of these have been left at spaces of from 10 to 20 feet 

 apart; they average a height of 18 feet and a girth of 15 inches. 

 Fed, of course, by the old roots, this growth far surpasses that from 

 seeds. In suitable locations, however, a wood-lot of A. melanoxylon 

 could be trusted to reproduce itself from the roots. The fuel value of 

 the wood is high. 



Other Acacias. A new collection of acacias was planted out in the 

 spring of 1901, and with previous plantings and a few set in the spring 

 of 1902, the total representation of acacias is now nearly thirty species. 

 One of the most striking of these is A. Baileyana, a very ornamental 

 tree. A. verticillata and A. linifolia } both species of small growth, have 

 attracted much attention. 



OAKS AND OTHER HARDWOOD TREES. 



English Oak (Quercus robur). The English oak has now received a 

 thorough test here on all the levels. Many trees promised well until about 

 1897. The largest, twelve years planted, now girth from 14 inches to 

 21 inches, a foot from the ground, and this would be excellent if the 

 trees were healthy. But four out of five of the trees this age are dead 

 or dying at the top. A few are 16 feet high; the tallest healthy tree is 

 but 13 feet. The growth is seriously affected, as elsewhere on the coast, 



