Canadian Forest]) Journal, April, 1919 



171 



STUDYING THE GROWTH OF TREES 



An interesting experimental project in fores- 

 try is under way at the Petawawa Military Res- 

 ervation, near Pembroke, Ontario, under the 

 guidance of the Dommion Forestry Branch. Mr. 

 H. C. Walhn IS directmg the work, assisted by 

 Mr. James Kay and Mr. George Clarkson. 



The object of the expriment station is to study 

 natural reproduction of white pine and red pine 

 chiefly, and to learn the effects of "thinning" 

 on the increment of individual trees and of the 

 whole stand. There will be an opportunity also 

 to study the effect of thinning on the condition 

 and character of the soil and ground cover, and 

 to get data for the construction of yield tables. 



The accom.panying picture shows the manner 

 of marking the trees with stencilled numbers. 

 Every tree, with complete information regarding 

 it, is entered on a map, so that growth and other 

 phenomena can be accurately guaged. 



remote from market, girdling the hardwoods is a step 

 that should be well considered, if the land is desired 

 to produce the maximum amount of softwoods for the 

 future. 



Subsequently in 1906 a certain section of the same 

 region west of McKean Falls known as a spruce 

 flat type was cut to a 12-inch diameter limit. As the 

 site was fairly well protected from windfall, most of 

 the older trees left are still standing. These trees on 

 account of their age show little or no increased 

 growth. They have, however, reseedcd the ground 

 splendidly and there is now a mixed stand of spruce 

 and fire coming up of 6 to 12 feet in height. The re- 

 maining stand might cut 3 to 4 cords to the acre. 

 But it would be unwise to go in now to log the 

 old trees on account of the increased cost of logging 

 due to the small cordage per acre obtainable, and 

 because it would be murdering the reproduction to 

 cut the older trees unless extreme care was taken, 

 and as the older trees will be subject to windfall and 

 decay before the young trees arc ripe for cutting, 

 much loss has been sustained and a saving could have 

 been made by cutting to a smaller diameter limit 

 originally, as fewer trees would have served as wcH 

 for reproduction. 



Windfall Takes a Big Toll. 



Still another cutting was made to a 10-inch dia- 

 meter limit in an uneven-aged stand in a region 

 known as a spruce flat merging into a hardwood 



type. This was done in the town of Grafton, 

 Maine, about ten years ago. Here the soil was 

 ! airly deep and as the situation was a low flat 

 valley between the mountains, it was thought to be 

 safe from heavy winds. In cutting here large 

 clumps of trees of small diameter were left intact 

 in a group system to protect each other from the 

 wind, and single trees up to 10 inches on the stump 

 in other places were left standing alone for seed 

 trees. The result was that the isolated trees were 

 practically all blown down, and ihc wind each year 

 slowly but surely took the clumps systematically, 

 tipping them over at the edges, which compelled the 

 company to return again and again at great cost 

 to salvage the blowdown, and finally to rescue what 

 remained standing. Reproduction under a 10-inch 

 stump limit was good, coming up particularly well 

 where all seed trees were left, the fir predominating. 

 Clean cutting in an even good softwood stand 

 in a typical softwood flat with a rocky, moist soil: 

 This was done around Lincoln Pond, in Parker- 

 town, Maine, where all the logs and pulpwood stand 

 were cut in in 1899 and 1902. The tree growth 

 was not extremely large, but very abundant. All 

 softwoods were cut clean and peeled for pulp. All 

 that remains of the old growth are a few scattering 

 hardwocds which are dying and a few very much 

 stunted and suppressed spruce 3 to 4 inches in 

 diameter and 10 to 20 feet high. Although these 

 trees have had plenty of light for the last 15 years, 



