West Virginia Seed Sources of Balsam Fir

Research Bulletin 1191-99

Lateral Branch Angle

Trees with ascending branch angles have a number of potential advantages for use as Christmas trees. The upswept limbs tend to cover the terminal shoot, generally making for a more conical and dense-appearing tree. Additionally, they tend to cover a greater length of the central stem, making it possible to leave longer leaders during shearing, thereby reducing the time needed to produce marketable trees. Using an angle gauge, branch angles (in degrees from the vertical) were measured for the uppermost whorl of limbs.

Differences Between Locations
Average branch angles for trees of the five West Virginia origins ranged from 24 to 28 degrees and were significantly smaller than those of trees from North Carolina (37 degrees,Table 5).

Differences Between Seed Sources
Trees of SS-390 from Stone Coal Run had the smallest average branch angle (19.0^o), while the branch angle was largest (41.1^o) for trees of SS-24 from North Carolina. For the one-third of the collections having the smallest branch angles, seven were from Stone Coal Run, four from Blister Swamp, three from Canaan Valley-State Park, two from Canaan Valley-Cortland Road, and one from Blister Run. Trees of collections having the largest branch angles were Blister Run with five, Canaan Valley-State Park with four, Canaan Valley-Cortland Road three, and Blister Swamp and North Carolina two each (Tables 3, 4, 5; Figure 11).

Figure 11. Branch angles of uppermost whorls of trees of SS 390 (Stone Coal Run, left) and SS 419 (Canaan Valley-Cortland Road, right).

Differences Within Seed Sources
The variation in branch angles within individual families/collections was generally large. Standard deviations ranged from 17 to 46 percent of individual family means, with those for trees of the two North Carolina origins being the lowest (17 and 20 percent, Table 5). For individual trees of SS-390 having the smallest average branch angle (19^o), the range in measurements was from 5 to 30^o, and for SS-24 having the largest branch angle (41^o), the range was from 30 to 55^o.