abnormal swelling of plant tissues caused by gall wasps, mites, nematodes, and various insects and less commonly by fungi or bacteria. Contrast with burl.

mechanism to control the opening and closing of a connecting device. See carabiner and snap.

taxonomic group, composed of species having similar fundamental traits. Botanical classification under the family level and above the specific epithet level.

synthetic fabric used in landscaping and in landscape or road construction applications as a barrier under mulch or pavement to reduce weed germination and growth, as a filter to reduce infiltration of fine soil into drainage or aeration structures (including tiles or pipes), as a barrier to separate and prevent infiltration of fill or paving layers (e.g., to prevent gravel paving from infiltrating a tree root zone), and/or to spread the load of a paving or fill layer and reduce compaction of an underlying layer. Geotextiles generally allow for the passage of water and for gaseous exchange but will be limited by the material placed above.

plant growth produced as a response to the force of gravity, either positive as in the direction of gravity (roots) or negative as in opposite the direction of gravity (shoots).

group of plant hormones involved in cell elongation and other physiological processes.

restriction or destruction of the vascular system within a root, stem, or branch that causes an inhibition of the flow of water and photosynthates in the phloem.

root that encircles all or part of the trunk of a tree or other roots and constricts the vascular tissue and inhibits secondary growth and the movement of water and photosynthates.

simple knot used to attach a line, spliced eye, or endless loop to an object.

wedge-shaped cut forming the front of a hinge used in tree or limb removal. See face notch.

(1) (noun) surface level of the ground. (2) (noun) the slope, or percentage of change, in the surface level of the ground; important for drainage and for the safe operation of equipment. (3) (verb) to change or groom the surface level or contours of the ground. (4) (noun and verb) quality determination for nursery stock.

phase of site development that provides a site with intended grades (contours, elevations, and slopes). Involves cutting and filling. See mass grading.

sheet of a complete set of development plans that depicts both original and finished (changed) grades. Essential information in developing tree conservation or preservation plans.

to join together tissues from the same or different plants in order to combine desirable characteristics or to effect a repair (bridge graft).

junction between root stock and scion wood. Often evident by a thickening of the trunk at the union.

water that drains from the larger soil macropores due to the force of gravity. Compare to available water, field capacity, permanent wilting point, and saturation point.

acronym for Good Rigging Control System, the brand name of a friction device used in rigging.

mulch composed of green (rather than woody) organic matter and not fully composted or decomposed. Also cut or mowed herbaceous material (grasses, etc.) that are left to decompose naturally and improve the underlying soil quality.

(1) the earth

metal rod used in grounding a tree lightning protection system.