Donations
A-SPI is a 501-3(c) Non-Profit

The Flea Market
Books, Tapes, and other Items.

THE PRACTICE OF ECOFORESTRY: ECOLOGICAL RESTORATION
Part 2 of 3

by Paul Kalisz, Ph.D.

1. Introduction.

The term ecological restoration refers to activities aimed
at repairing human-caused injuries to forest ecosystems, and
restoring natural levels of ecosystem health and integrity. As
noted in the introduction to Part 1, restoration and protection
of native ecosystems are the transcendent goals of ecoforestry.
This paper considers some practical activities that further these
goals. Part 3 of this series (þTending and Harvestþ) then
considers how people may obtain wood products within the
overriding constraint that restoration and protection of forest
health and integrity come first.

2. Basic Principles

The health and sustainability of human communities are
dependent on the health of the natural ecosystems in which the
communities exist. The health of natural ecosystems, in turn, is
dependent on the integrity of the web of life: all aspects of
natural biodiversity, ecological relationships and interactions.
Biodiversity includes diversity in the species that form the
living part of the ecosystem; diversity in the structure (how
the parts of the ecosystem are arranged both vertically and
horizontally) of the living and non-living components; diversity
in the functions that occur; and diversity in the underlying gene
pool. High levels of structural diversity are associated with
high levels of both species and functional diversity. Similarly,
high levels of plant species diversity are associated with high
levels of animal species diversity. Although ecosystems are
variable over time and space, high levels of biodiversity buffer
fluctuations. Compared to degraded ecosystems, ecosystems with
undiminished levels of biodiversity would be expected to resist
drastic and abrupt alterations of their natural properties,
processes, and dynamics, including their natural directions and
rates of change in space and time. We must begin now to undo our
past mistakes, by restoring and protecting natural ecosystems, if
we want to provide future generations with the opportunity to
live healthy and dignified lifestyles.

The following recommendations emphasize observation,
measurement, and manipulation of plants as an approach to the
restoration and protection of entire ecosystems. This is a
reasonable approach since plants are more easily observed and
manipulated that animals or other ecosystem components, and since
green plants are the basis for all life on Earth. Restoration
programs based primarily on the manipulation of plants will
result in restoration of the overall ecosystem.

3. Importance and Diversity Measures

A number of quantitative indices may be used as measures of
the importance of individual species, and of the diversity of all
the species on an area of land. Relative density and relative
basal area, or the average of the two, are often used as measures
of the importance of individual species (Example 1).

EXAMPLE 1

Total density = 400 stems/ac and basal area = 100 sq.ft/ac.
Red Oak density = 80 stems/ac and basal area = 50 sq.ft/ac.
Red Oak importance (density) = 20% [(80 --- 400) X 100]
Red Oak importance (basal area ) = 50% [(50 --- 100) X 100]
Red oak importance (average) = 35% [(20 + 50) --- 2]

Species richness (the total number of species) is the simplest
measure of species diversity for an area. A more complicated
index is called C (diversity index):

C = 1 - (SUM pi2 )
Where:
pi = the importance of species þIþ,
expressed as a decimal fraction

The importance value for each species is squared, then all of the
squared importance values are summed together and subtracted from
one. This index considers not only the total number but also the
importance of the individual species, and increases as the number
of species increases and as species become more uniform in
importance.

EXAMPLE 2

STAND 1
STAND 2
Total basal area = 100 sq.ft/ac.
Total basal area = 100 sq.ft/ac
Red Oak basal area = 25 sq.ft/ac & Importance = 0.25 Red Oak basal
area = 10 sq.ft/ac. & Importance = 0.10
Yellow-poplar basal area = 25 sq.ft/ac & Importance = 0.25 Yellow-poplar basal
area = 70 sq.ft/ac & Importance = 0.70
Basswood basal area = 20 sq.ft/ac & Importance = 0.20 Basswood basal
area = 10 sq.ft/ac & Importance = 0.10
Ash basal area = 30 sq.ft/ac & Importance = 0.30 Ash basal
area = 10 sq.ft/ac & Importance = 0.10

Species Richness, S = 4
Species Richness, S = 4
Diversity Index, C = 0.74
Diversity Index, C = 0.48

4. Restoration and Protection

Snags, Logs, And Windthrow Mounds-and-Pits

Snags (standing dead trees), logs (fallen dead trees) , and
windthrow mounds-and-pits (small hillocks and pits that form when
a tree uproots) are the biological legacy that one generation of
trees bequeaths to the next. All three types of biological
legacy provide unique habitats for organisms and increase the
structural diversity of the forest. It is estimated that as many
as 20% of all forest animals may rely on dead wood at some stage
of their life-cycles. The biological legacy, to a large degree,
distinguishes natural forests, and especially old-growth forests,
from young managed forests and plantations.

The natural abundance of snags in hardwood stands ranges from 1
to 10/ ac. Your inventory estimates of the number of snags per
acre in various height and DBH classes (see Part 1 of this
series) may be "scored" (Table 1) and then used to compare snag
density on your land to the þtargetþ densities found in natural
stands. For example, the target score of 100 for snags could be
achieved with approximately 25 snags/ac that are 10 inch DBH and
30 feet tall; with 3 snags/ac that are 20 inches DBH and 60 feet
tall; or with 1 snag/ac that is 30 inches DBH and 60 feet tall
(Table 1).



HEIGHT (ft)
30
60 90
DBH(in) Logs Snags Logs
Snags Logs Snags
10 10 4 20
10 30 17
15 ----- ----- 50
20 70 35
20 ----- ----- 80
35 120 55
25 ----- ----- 120
60 200 90
30 ----- ----- 200
100 300 100

Table 1. Scores for restoration of snags and logs. TO USE: Multiply the
average number of logs (or snags) recorded per acre in each height and DBH
class by the score for that class, then add the totals for all height and
DBH classes together. To achieve the target values, snag scores should
=100, and log scores should = 1000.

Approximately 10 tons/ac of wood naturally occurs as logs in
older stands of eastern hardwoods. Although this seems like a
lot, the mass of logs in our forests is small compared to the 250
tons/ac of logs that typically occur in old-growth coniferous
forests of the Pacific Northwest. As with the evaluation of snag
density, your inventory results may be used in conjunction with
the scores in Table 1 to evaluate log density on your land
relative to natural target values. In the case of logs,
inventory estimates of the number of logs per acre in various
height and DBH classes are converted to scores and compared to a
target score of 1000. For example, the target is achieved with
approximately 100 logs/ac that are 10 inches DBH and 30 feet
long; with 8 logs/ac that are 20 inches DBH and 90 feet long; and
with 3 logs/ac that are 30 inches DBH and 90 feet long. Note that
height (or length) in this case refers to the total height (or
length) of the snag (or of the fallen tree that formed the log)
rather than only to the portion of the tree trunk that is
normally considered a log.

The density of snags and logs may be increased by killing or
cutting trees. Snags are formed by girdling trees (cutting
through the bark and outer wood around the entire circumference),
and logs are formed by cutting trees and leaving them lying in
the woods. Theoretically, cavity trees ( living trees that are
hollow and used as dens by animals) may also be formed by
partially girdling but not killing trees. Artificial production
of snags and cavity trees is not recommended since girdled trees
rot from the outside in, rather than from the inside out as
occurs in cavity trees and snags. Rather than trying
artificially to increase their numbers, you should protect all
natural snags and cavity trees until their density approximates
the target densities. This practice is contrary to the natural
tendency to cut decayed, dying or dead trees first when
harvesting trees for firewood or other products.

If substantial numbers of trees are cut and left as logs,
it is usually advisable to cut the finer branches and spread them
on the ground to prevent accumulation of fine, dry fuels that
might increase the wildfire hazard. The felling of large trees
must always be done with care to prevent breakage or wounding of
surrounding trees.

In the Appalachians, the density of treethrow mounds-and-
pits ranges from 20/ac to 50/ac. Densities are usually higher
and individual mounds-and-pits are usually larger in coves and
other moist sites than on dry sites such as ridge tops. Although
there is no practical way to increase the density of mounds-and-
pits, you should recognize that mounds-and-pits are part of the
local microtopography (small scale irregularities in the land
surface) that contributes to the overall structural diversity of
the ecosystem. Mounds-and-pits should be monitored and protected
from disturbance.

Old-Growth Forests

In eastern hardwoods, old-growth forest stands generally
contain many canopy layers (distinct layers occupied by living
branches with green foliage); a variety of tree species; a
variety of tree heights and DBHs; a variety of tree ages (uneven-
aged structure); some trees over 200 years old; and an abundance
of cavity trees, snags, and logs. Due to past clearcut logging
and to attempts to convert all stands to an even-aged structure
(stands with trees that are all of approximately the same age),
old-growth stands are now rare. All old-growth should be
protected. In addition, attempts should be made to restore old-
growth using the techniques discussed in this paper and in Part 3
(þTending and Harvestþ) of this series.

Sensitive, Threatened and Endangered Habitats and Species

You should obtain federal and state lists of threatened and
endangered species that may occur on your land. In order to
foster and protect these species you should also become familiar
with their habitats and special requirements. Cliff lines,
caves, and riparian zones (the areas around streams or ponds)
should be protected since they provide a variety of unique
habitats and have high levels of natural biodiversity. In the
Appalachians, threatened and endangered plants and animals such
as White-Haired Goldenrod, the Allegheny Woodrat, the Virginia
Big-Eared Bat, and the Green Salamander utilize caves and cliffs.
þNo-use zonesþ about twice the average mature height of the
tallest tree species native to the site should be established to
either side of cliff lines and streams, and surrounding cave
entrances and natural ponds. Caves, in particular, are
vulnerable to temperature changes and to air and water pollution.
Care should be exercised in cutting trees near caves and in
locating camps relative to cave entrances. Careless removal of
even a few trees, especially trees shading south-facing caves
and cliff lines, may increase sunlight and temperature enough to
eliminate sensitive plants and animals. Smoke from fires may
also be sucked into caves and adversely affect air quality for
many years or decades as the smoke slowly circulates throughout
the cave system.

Exterminated and Declining Species

Native species that have been locally exterminated, or
species that are in imminent danger of being locally
exterminated, may be re-introduced or nurtured. It is easier to
re-introduce plants than animals since plants are conveniently
collected and transferred as cuttings, seeds, or seedlings. Re-
introductions should always be made from a nearby population,
since introductions of non-local genotypes may lead to the
elimination of local genotypes. Species such as American
Chestnut, Flowering Dogwood and Butternut, which are in decline
due to human-induced degradation of ecosystems, should be
nurtured and protected. As a starting point for this effort,
up-to-date scientific information on symptoms and treatment of
conditions such as Chestnut Blight, Dogwood Anthracnose, and
Butternut Canker may be obtained from your county extension
agent, from your stateþs division of forestry, from the forestry
department of your stateþs land-grant university, from local
offices of the U.S. Forest Service, or by computer from any of a
growing number of sites on the Internet.

Elimination and Control Roads

Road-building is perhaps the single most destructive human
activity on forest lands. Roads are a form of forest
fragmentation (breaking-up of extensive tracts of forests into
relatively small patches separated by non-forested land) and
contribute to many types of ecosystem degradation including:
isolation of small populations of non-mobile organisms;
alteration of forest climate; direct mortality due to road-kill;
disruption of animal movements; disruption of water flow
patterns; increased incidence of tree damage by wind, snow and
ice; increases in soil erosion; introductions of exotic species;
increases in numbers of opportunistic predators such as Raccoons
and Cowbirds; increases in human disturbances due to noise, fire,
litter, pets, poaching, gathering dead wood, trampling and
compacting soil, off-road vehicle use, and cutting trees.
Research has found a critical road density just under 1 mile of
roads per square mile of land area. Above this critical density
animal movements and other ecosystem processes and properties are
severely and adversely affected. Any program of ecological
restoration of forests should therefore aim to reduce road
density below 1 mi/mi2 using whatever effort and technology is
required to first close and then to rehabilitate road beds. The
box below describes a simple and accurate method for estimating
road density on a map to determine if the existing density
exceeds the critical value.

Line-Intersect Method of Estimating Road Length

1. Delineate the land area of interest on a map. Calculations are easiest
if the area is some regular shape (square, rectangle, triangle, etc.) for
which the land area may easily be calculated. Although not absolutely
necessary, subsequent steps are easier if you darken the road system you
are interested in with a pen.

2. Use the scale on the map to determine the area (in units of square
miles) of the land that you have delineated.

3. Completely cover your delineated area with vertical and horizontal lines
that form a square grid having a unit length of 1/4-inches. The grid may be
drawn directly on a copy of your map, or, better yet, may be put on a piece
of clear plastic that can be used repeatedly as a map overlay.

4. Randomly place the grid over your map. Follow each vertical line of the
grid and record the number of times a road intersects a grid line (not a
grid corner). Repeat this procedure for the horizontal grid lines. Add the
two numbers together to get the total number of times roads intersected
grid lines.

5. Multiply your total number of intersections by 0.2 to get an estimate of
the number of inches of road on your delineated land area. Use the map
scale to convert inches of road on the map to miles of road on the ground.
> On a standard USGS topographic map, the scale is 1:24,000. This means
that 1 inch on the map represents 24,0000 inches = 2,000 feet = 0.4 miles
on the ground.
>A square land area 3-3/4 inches on a side would be equivalent to: [(3.75 X
0.4) X (3.75 X 0.4)] = 2.25 square miles.
>A count of 27 road intersections with vertical grid lines and 25
intersections with horizontal grid lines = 52 total intersections.
>52 intersections X 0.2 = 10.4 inches of roads on your map.
>10.4 inches X 0.4 miles/inch = 4.2 miles of road in your delineated area.
>4.2 miles road --- 2.25 sq.miles land area = 1.8 miles road per square
mile land area.

Exotic Species

Exotic plant and animal species are common in degraded
ecosystems. Although exotic species such as Starlings and
Dandelions may be here to stay, efforts at exotic species control
should be part of all ecological restoration programs. Exotic
plants may be eradicated by pulling or cutting when they are
young, but control becomes more difficult once plants are
established. Animals such as goats have been successfully used
to eradicate Kudzu from pastures, but domestic animals need to be
used with caution to prevent them from doing more harm than good
to the forest ecosystem. Prescribed fires (fires that are
intentionally set and controlled to achieve a specific objective)
may also be effective in controlling exotic plants in certain
situations. Chemical controls are never recommended since they
almost always have unanticipated and negative effects on non-
target organisms. Consult local sources of information concerning
the occurrence and control of important exotic pest species in
your area.