. The Canadian field-naturalist. 1983 Notes 105 (0 4-1 0) E 0) 0 c 0) o 100 • it « 80 — - • X 60 — • filled seed X empty seed • • ? seed airborne at 100 m 40 — • X • • X 20 — • • •• • . • •X • 'X • n - X • • • • X 1*1 1 1 • 1 . 1 1 1 1 1 1 1 20 40 60 80 Time (seconds) 100 120 140 Figure I. Relationship of airborne time and distance seed landed from tree for the primary phase of seed dispersal in White Spruce. from the tree (Figure 1). Average time airborne was 38 ± 21 s. The average rate of fall was ± m/ s (range to ). Schlesinger( 1970) reported a rate of fall of ± m/ s
. The Canadian field-naturalist. 1983 Notes 105 (0 4-1 0) E 0) 0 c 0) o 100 • it « 80 — - • X 60 — • filled seed X empty seed • • ? seed airborne at 100 m 40 — • X • • X 20 — • • •• • . • •X • 'X • n - X • • • • X 1*1 1 1 • 1 . 1 1 1 1 1 1 1 20 40 60 80 Time (seconds) 100 120 140 Figure I. Relationship of airborne time and distance seed landed from tree for the primary phase of seed dispersal in White Spruce. from the tree (Figure 1). Average time airborne was 38 ± 21 s. The average rate of fall was ± m/ s (range to ). Schlesinger( 1970) reported a rate of fall of ± m/ s for White Spruce seed in still air. The distance of a seed's landing from a tree did not necessarily indicate its actual airborne distance tra- velled. During flight an individual seed can follow a very circuitous path. The extent and nature of horiz- ontal and vertical movement is determined by the wind and air turbulence encountered. An example is one seed that travelled about 121m yet landed only 13 m from the tree. During dispersal, this seed expe- rienced two periods of upward and three of downward flight (Figure 2). The height reached by seeds traveling up and out of sight shortly after leaving the cone could not be determined. These observations, however, indicate that the greatest height attained by a White Spruce seed may exceed the height of the cone from which it came. These seeds have the potential for longer dis-. Lttgand ^^^ Flight of seed 1 ~ —— Flight of seed 2 Numeral indicates distance on that leg of flight; U or D indicates up or down movement of the seed during flight. Figure 2. Flight path of two White Spruce seeds during primary dispersal (seed ! landed 13 m from tree and was in flight 71 s; seed 11 > 100 mand> 125 s).. Please note that these images are extracted from scanned page images that may have been digitally enhanced for readability - coloration and appearance of these illustrations
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