Foliage shedding in deciduous forests lifts up long-distance seed dispersal by wind

Nathan et al. 10.1073/pnas.0503048102.

Supporting Information

Files in this Data Supplement:

Supporting Methods
Supporting Table 1
Supporting Figure 4
Supporting Table 2
Supporting Figure 5
Supporting Figure 6

Supporting Figure 4

Fig. 4. Seasonal histograms of the measured friction velocity (

) during seed dispersal periods fitted to a Weibull distribution.

Supporting Figure 5

Fig. 5. Testing the Eulerian component of CELC against published canopy turbulence data [Finnigan, J. (2000) Annu. Rev. Fluid Mech. 32, 519-571] for a wide range of canopy morphologies ranging from sparse (LAI = 2 m² m^-2) to dense (LAI = 6 m² m^-2), short (h = 0.75 m) to tall (h = 30 m), and constant to heterogeneous leaf area density profile variation (left column). The canopies tested here include rice, corn, aspen, loblolly pine, Scots pine, and a southeastern Hardwood forest (which is analogous to our study site).

Supporting Figure 6

Fig. 6. Sensitivity analysis for the modeled dispersal distances traveled by uplifted seeds D_uplifted normalized by canopy height h, with respect to the dimensionless variable

for LAI = 1, 2, . . . ,5, where

is the friction velocity above the canopy, V_t is the seed terminal velocity, and H_r is the mean seed release height. The solid line is the log-log regression to the model data.

Table 1. Shape and scale parameters of the Weibull distribution fitted to the friction velocity (u_*) calculated from wind velocity measurements recorded at 10-Hz at the tower, 40 m above the floor of a 33-m high forest

Period	Shape parameter b	Scale Parameter c	R²	P (slope = 0)
Nov 2 – Dec 7, 2000	0.34	1.33	0.94	< 10^-5
Oct 19 – Dec 28, 2001	0.32	1.37	0.96	< 10^-5
Nov 6 – Dec 30, 2002	0.40	1.48	0.96	< 10^-5
Mar 29 – May 17, 2002	0.45	1.47	0.94	< 10^-5
Nov 2, 2000 – Dec 30, 2002	0.36	1.37	0.96	< 10^-5

Goodness of fit is evaluated by linear regression (measured = intercept + slope _* modeled).

Table 2. Published canopy sublayer velocity measurements collected from a wide range of leaf area density, leaf area index (LAI), and canopy height (h)

Canopy type	h, m	LAI, m m^-2	C_d
Rice	0.72	3.1	0.2
Corn	2.21	2.9	0.3
Aspen	10.0	4.0	0.2*
Loblolly pine	14.0	3.8	0.2
Scots pine	20.0	2.0	0.2
Oak-hickory-pine	23.0	5.0	0.15

The published drag coefficient C_d is also shown. All model calculations are conducted assuming standard atmospheric surface layer values for A_u (= 2.7), A_u (= 2.4), A_w (= 1.25) (e.g., ref. 1), and for a = 0.06 (1).

*The value is assumed.

1. Finnigan, J. (2000) Annu. Rev. Fluid Mech. 32, 519-571.