Design - Project Planning and Management for Ecological Restoration - page 91

factors and to make compromises. For in-
stance, by providing a high level of mainte-
nance in figure 6-6d, you should be able to
control the unwanted establishment of ex-
otics. So, if these two factors are of concern
for your project, then by providing mainte-
nance you simultaneously address the exot-
ics issue, but only if the maintenance bud-
get includes weeding. Given this situation,
you can design a project with less dense
plantings. However, if your permits or stake-
holders are expecting a certain level of per-
formance, you will have to incorporate this
into your design thinking. In the area of en-
vironmental stressors, your site analysis may
have addressed a number of these and the
overall construction plan may be removing
some or all of them. The remaining stressors
may have a bearing on your planting density
decision. From this simple set of graphs you
can visualize the relationship that the vari-
ous factors have and how they will influence
your decision on the final design.
These examples are designed to illustrate
the relationship of one factor to another. In
the final analysis, the ultimate aim is to have
the planting attain a level of self-sufficiency
and then further develop and mature into
the prescribed type of vegetation commu-
nity. While the drawings of the plans may
show discrete circles, polygons, and similar
symbols, the intent is not that these species
should only remain or even continue in
these locations. We are not interpreting the
plans as if they were landscape architecture
drawings that are meant to be site specific
with little to no variation. Our ultimate pur-
pose is to introduce the species onto the site
and permit the species to survive wherever
they find suitable microhabitat. We start the
process by making determinations where we

FIGURE 6-9. (Top) In areas with significant stressor
influences (temperature, moisture, wind, insect
infestation), a higher than normal planting density
will increase the probability of a sufficient number
of plants surviving.

FIGURE 6-10. (Bottom) Sites with a high intensity
of maintenance will permit lower planting density
because stressors will be controlled, increasing the
likelihood of higher plant survival.