|
|
||
 Appendix B: Bioengineering for Streambank Erosion Control -- Guidelines
Handling of Plant Materials
Plants need to be handled carefully to ensure their survival between the phases of
acquisition (purchasing, growing, or harvesting from the wild) and transplanting because they
will undergo transportation and planting shock. Many problems associated with poor plant
survival occur from the handling of the plants between the nursery or collection site and the
project planting site. Generally, the plant material needs to be kept cool, moist, and shaded
(Hoag, 1994). They must be treated as living material; if the living attributes are lost, then
the project is much more prone to fail even though dead plant materials in a bioengineering
treatment can offer some erosion control through their physical attributes, e.g., acting as bank
armor, runoff retention through checkdam effects, current and wave deflectors. Plants are
most easily collected when dormant. When plants are dormant, there is substantially more
forgiveness in how they are handled.
Woody Plants. Woody plants, particularly cuttings, should be collected when dormant;
their survival decreases a lot if they are harvested and planted in a non-dormant state. With
bareroot or unrooted cuttings, keep them cool, moist, and in the dark until they are ready to
be planted (Hoag, 1994b). They can be stored in a large cooler at 24-32 deg F until just
before planting. Cuttings can be stored in this manner for several months (Platts et al. 1987).
The cuttings can be kept in a cooler, root cellar, garage, shop floor, or any place that is dark,
moist, and cool at all times (Hoag, 1994b). Often, cuttings are placed on burlap and covered
with sawdust or peat moss and then covered with burlap after being moistened.
Hoag (1994b) advocates soaking of cuttings for a minimum of 24 hours, whether they are
coming out of storage or directly after harvesting in the late winter to early spring (Hoag et
al. 1991a; Hoag et al. 1991b; Hoag 1992). Some research recommends soaking the cuttings
for as much as 10-14 days (Briggs and Munda 1992; Fenchel et al. 1988). The main criteria
is that the cuttings need to be removed from the water prior to root emergence from the bark.
This normally takes 7 to 9 days (Peterson and Phipps 1976). Soaking is important because
it initiates the root growth process within the inner layer of bark in willows and poplars
(Hoag, 1994b).
When woody plants are moved from the nursery, holding, or harvesting area, to the
project site, they should continue to receive careful handling by keeping them moist and free
from wind dessication. The latter can be achieved by ensuring they are covered with a light-
colored (to reflect heat) and moist tarp. In the case of cuttings, they can be moved to the
project site by moving them in barrels with water in them or some similar method. Actual
planting of the plants shall follow the digging of holes as soon as possible, preferably no
longer than 2-3 minutes, so that the excavated soil does not dry out. Use only the moist,
excavated soil for backfill of the planting hole. Backfill should be tamped firmly to eliminate
all voids and to obtain close contact between the root systems and the native soils. When
using containerized or balled and burlap stock, excess soil should be smoother and firmed
around the plants leaving a slight depression to collect rainfall. Plants should be placed 1 to
2 inches lower than they were grown in the nursery to provide a soil cover over the root
system (Leiser, 1994).
B-76
|
||
|
||
