Terminology

Common Terms

A 

Allelopathy - the excretion of chemical compounds by plants to inhibit the growth of neighboring plants, increasing the former's competitive advantage. In this course, you should know two species that do this: tall fescue (Festuca arundinacea a.k.a. Schedonorus arundinaceus), and walnut species.

Arboriculture - The holistic maintenance and management of trees at an individual level, while taking into account the urban ecosystem and the environment that the tree is planted in.

B

Balled and Burlapped (B & B) production system

Bare root production system

Base course - Gravel and stone designed to make a stable base for roads and sidewalks. Does not hold water, making it stronger.

Branch collar - Technically a branch "socket": it is a structure formed on the main trunk around a branch formed by vascular tissues (basically wood) from both the branch and the trunk. It appears as a swollen area around the base of the branch.

Bulk density: Ms / Vt

C

Container-grown production system

Cane - The major stem originating directly from the basal area of a shrub

D

Defect - A possible characteristic that could lead to tree failure.

E

Elemental sulfur - this can be applied to lower soil pH. 

F

Failure - a very special, arboriculture-specific term that refers to a part of a tree breaking off or falling down. A " branch failed" means that a branch has fallen off. A "tree failed" means that the entire tree fell down. 

 

G

Graft union - The place on a grafted tree where the scion meets the rootstock. This can be another point of structural weakness due to the possibility of graft incompatibility.

H

I

Included bark - Tree bark that has been sandwiched or enclosed between a branch angle (crotch). This is a major structural weak point of a tree.

J

K

L

Limestone/Lime - Gravel/infrastructure material that can raise the soil pH dramatically. Typically a nuisance for arboriculture and urban soils.

live-crown ratio:  the ratio of live-crown to tree height expressed in percentage.

 

M

N

O

P

Q

R

Risk - the possibility of something undesirable or destructive happening. In this case, the "risk" of a tree is considered in terms of dangers to humans. So if a tree falls on a wilderness space far from people traffic, the risk is considered "low" or even zero.

Root turnover - The number of times the root biomass is replaced each year.

 

S

Soil Structure -- The soil Ratio between Pore & Matrix.

Soil Texture - The relative proportions of sand, silt, and clay in a soil.

 

T

Target - anything that might be damaged by a tree failure.

U

V

W

X

Y

Z