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Glossary: B is for ... bark, biomass, and boreal
by Ariadne Unst
Glossary of B...
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- banner (n.)
- The upper petal of a pea-like flower.
- bark (n.)
- The skin or covering of branches and roots of a tree.
A relatively waterproof layer that protects the tree
from insects, fungus, etc.,
and stops it from drying out.
As the trunk grows, for many trees, the bark cracks as it expanded around the trees.
- beak (n.)
- A firm and pointed terminal appendage.
- bedrock (n.)
- Solid, unweathered rock close to the Earth's surface.
- A simple, pulpy fruit developed from a single ovary. The fruit may contain
few or many seeds, but no stones.
- B horizon (n.)
- The soil horizon below
the A horizon
the C horizon.
In this layer, clay is enriched because of being washed down from
the A horizon.
Iron and aluminum oxides are similarly enriched. (Sometimes
the precipitation of iron can cause the development of a hardpan.)
Calcium carbonate, calcium sulfate, and other salts also accumulate.
- biennial (n.)
- A plant with a two-year life cycle. Usually it grows only stems and leaves in the first year;
in the second year it flowers, seeds, and dies.
- bifurcation ratio (n.)
- Quantitative ratio between parts of systems that display branching.
In particular, a tree's trunk bifurcates into smaller branches,
which in turn bifurcate or branch. The ratio between the
branches that are derived from a larger branch or main stem is the
- biodiversity (n.)
- Biological diversity. It includes:
species diversity (that is, diverse species),
genetic diversity (the genetic variability among individuals within each species), and
ecosystem diversity (the variety of ecosystems).
- biomass (n.)
- Total mass of a species or group of organisms in a particular
The commercially sponsored California Forest Products Commission
reports (1999) forest biomass as
"all the plant material above the ground in a forest".
Years of fire suppression leaves forests with increased ground-level tinder and fire hazard.
Harvesting some of the trees:
- Removes nutrients from the forest, thereby weakening and stressing the remaining trees.
CFPC claimes that
"An area can be harvested for biomass every 15 to 20 years."
- Does not reduce likelihood of ground fire unless the ground-level plants are removed.
CFPC recognises the problem of loss of nutrients by reporting:
"Often the tree limbs are left on the ground to decompose and return nutrients to the soil and protect it from erosion."
This allows a portion of the nutrients to return to the soil, although of course for a while the artificial addition of
these branches to the floor increases the fuel for a ground-level fire.
- Does not reduce likelihood of a ground fire laddering up the trees into a crown fire,
unless significant reduction is made in branches and shrubs that help the fire climb to the crown.
- If mills burn wood to generate electricity, they are removing nutrients from the forest
and they are adding greenhouse gasses to the atmosphere.
- biome (n.)
- A geographic region distinguished by temperature and precipitation and the resulting vegetation.
It contains a varying number of
- biosphere (n.)
- The portion of the Earth that supports life.
- biotic factor (n.)
- A living organism as well as the products of living organism
(such as fallen leaves, feces, shells, and skeletons of dead creatures).
- biotic potential (n.)
- The powers of a population to increase.
- bisexual (adj.)
- Has stamens and pistils.
- blade (n.)
- The expanded leaf or petal;
the leaf excluding the stalk.
- boreal (adj.)
- Northern. Opposite of
- boreal forest (adj.)
- Forest of High to mid latitudes; dominated by coniferous forest.
Predominant tree species are spruce, fir, pine, and cedars.
- bract (n.)
- A modified leaf or a reduced leaf, which appears over or under or in association with a flower cluster;
the scale-like leaves of an
- breed (n.)
- A race or strain cultivated by humans.
- brown earth (also, brown forest
- Below a litter layer and a humus layer, this first layer of true soil is
dark and humus-rich. Such earth is usually acidic, never alkaline, and often
develops over clays. It grades into slightly lighter colored subsoils.
- bryophyte (n.)
- A subdivision
Includes mosses and liverworts.
- bud (n.)
- An undeveloped stem, branch, or shoot of a plant. It holds undeveloped,
preliminary leaves or flowers.
- bulb (n.)
- An underground food store of a plant; derived from a shoot
enclosed in thick, overlapping, leafy scales.
- bundle scar (n.)
- The scar that is left on a twig after a leaf falls.
- burl (n.)
- A woody swelling where the stem joins the roots.
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