Poplars Can Be Bred to Order 



155 



In 1947 we started once more to 

 build up our growing stock of 200 

 selected hybrids for comprehensive 

 forestation tests throughout the North- 

 east. We hope this time to be able to 

 complete the job. Research with liv- 

 ing trees cannot be slowed down, 

 stopped, and started again, without 

 loss of results out of all proportion to 

 the length of the inactive period. Na- 

 ture keeps her steady pace without 

 regard for depressions and wars; trees 

 that can be transplanted this spring 

 will be too large next year; trees that 

 are dying this month can provide 

 symptoms of their malady if they are 

 examined in time, but next month may 

 be too late; a thinning in hybrid poplar 

 delayed a year can result in more than 

 merely retarded growth it can start 

 the entire stand on the road to de- 

 generation. 



DURING OUR YEARS of work with it, 

 we have thought of the hybrid poplar 

 as the farmer's tree a tree that can 

 provide a forest income for many 

 farmers, with marginal land and de- 

 pleted wood lots, earlier than the slow- 

 growing species can. 



The rapid growth of the hybrids 

 has been demonstrated in the original 

 plantations in western Maine, where 

 the growing season is relatively short. 

 They were planted 6 by 6 feet apart on 

 farm land abandoned about 60 years 

 ago. They were never thinned (con- 

 trary to good practice) because we 

 wanted to let natural selection elimi- 

 nate the weak. 



Judging from the growth of the se- 

 lected hybrids in the unthinned plan- 

 tations, we can predict that with good 

 forestry methods the poplar hybrids 

 will produce at least 40 cords of wood 

 an acre in 15 years. The prediction is 

 based on the actual growth of indi- 

 vidual hybrids whose equally vigorous 

 neighbors gave them far greater 

 competition than would be permitted 

 under good forestry. At the prewar 

 roadside price of $8 a cord, we figure a 

 gross income of $320 for 40 cords an 

 acre over 15 years 10 cords an acre 



from thinnings between the eighth and 

 tenth years, and 30 cords an acre at 15 

 years. Properly thinned stands need 

 not be cut in 15 years; in 20 to 25 years 

 they would produce logs for veneer or 

 lumber. 



As for net income, a farmer would 

 calculate the amount of work he would 

 have to do on his plantation. Each 

 newly planted acre will require ap- 

 proximately 10 days of work from 

 planting to harvest, of which all but 

 the planting and cultivation in the 

 first year can be done during slack 

 seasons. The work of the first year 

 (preparation of land, planting, and 

 cultivation, which would take 4 man- 

 days an acre) would be required only 

 once when the timber is harvested 

 the hybrid poplars will regenerate 

 themselves from root suckers. In the 

 third or fourth year, thinning the trees 

 would take 1 man-day an acre. Be- 

 tween the eighth and tenth year, thin- 

 ning would require approximately 5 

 man-days an acre. Besides work re- 

 quired to grow the crop, there will be 

 the harvest labor, which can also be 

 handled as a winter or off-season job. 

 If the farmer does the work himself, 

 he simply transfers the difference be- 

 tween gross and net income from one 

 pocket to the other ; if the work is done 

 by hired labor, the net income will 

 compare favorably with that from 

 many other farm crops. 



These estimates are based on growth 

 in Maine, where the growing season is 

 short. With a longer growing season, 

 the hybrids will grow faster. Dormant 

 cuttings (12-inch lengths of 1 -year-old 

 stems without roots) of 102 different 

 hybrids were planted at the Agricul- 

 tural Research Center in Maryland in 

 the spring of 1947. Fifty of them grew 

 to an average height of 6 to 8 feet in a 

 year. In 1 year from cuttings, the same 

 hybrids would grow only 2 /a to 3 feet 

 in Maine and 4 to 5 feet in western 

 Massachusetts. 



OTHER CHARACTERISTICS than rapid 

 growth have been considered in mak- 

 ing the selections. The hybrids were 



