Arboriculture Glossary of Terms
d
- disease complexcombination of factors contributing to the stress or decline of a tree.
- disorderabnormal condition that impairs the performance of one or more vital functions. Often associated with noninfectious agents or abiotic factors (contrast with disease).
- Disteltype of friction hitch used in climbing and rigging.
- divisionphylum. Taxonomic group below the kingdom level but above the class level.
- division phylumtaxonomic group below the kingdom level but above the class level.
- dominant leaderthe one stem that grows much larger than all other stems and branches; at least one third larger than lateral branches nearby.
- dormancyperiod of naturally reduced physiological activity in the organs of a plant with the potential for reactivation of growth.
- dormantin a period of dormancy.
- dormant budbud originally developed in a leaf axil and connected to the pith by a bud trace that has not been stimulated to mature and grow. Some buds remain dormant throughout the life of a woody plant.
- dormant oilssee horticultural oils.
- double braidrope construction consisting of a braided core within a braided rope. both of which carry part of the load (contrast with kernmantle rope).
- double crotchtechnique consisting of tying one climbing line or two climbing lines into two places in a tree.
- double figure-S knotfigure-8 knot tied with two strands of rope.
- double fisherman's bendin arboriculture. the name used for a knot that is commonly used to join two ropes or two ends of the same rope. as when forming a Prusik loop. Grapevine knot.
- double half hitchtwo half hitches tied in a series.
- double hitchtechnique consisting of securing a tree section with two load lines in rigging.
- double-lockingpertaining to a carabiner. requiring two distinct motions to prepare the gate to open.
- double serratetoothed margin of a leaf. with smaller teeth within the teeth.
- downy mildewany of various oomycetes (not true fungi) producing white. fungal-like growth that develops during wet periods. usually on the underside of a leaf (contrast with powdery mildew).
- Dracaena reflexa Song of IndiaDracaena reflexa Song of India
- Dracontomelon duperreanumYanmin
- drift linein tree rigging. variation on the load transfer technique in which the load is transferred to a second line and moved to another point. often to a second tree.
- drill-hole fertilizationapplying fertilizer by drilling holes in the soil within the root zone (contrast with broadcast fertilization and liquid fertilization).
- drip irrigationmethod of minimizing evaporation and runoff by applying small amounts of water through small emitters.
- drip lineimaginary line defined by the branch spread of a single plant or group of plants.
- dropcrotch pruning (obsolete) term for a method of reducing the height of a tree. The general rule for cuts is that leaders should be cut back to a lateral capable of assuming apical dominance. if possible. usually at least one third the diameter of the leader. See reduction.
- drop-crotch pruning(obsolete) term for a method of reducing the height of a tree. The general rule for cuts is that leaders should be cut back to a lateral capable of assuming apical dominance. impossible. usually at least one-third the diameter of the leader (see reduction).
- drop cutbranch-removal technique consisting of an undercut and then a top cut. usually made farther out on the branch. or with a chain saw. directly over the undercut.
- drop linerope used to secure the weight of a limb in rigging; load line.
- drop starttechnique used to start a chain saw by pushing the saw away from the body and simultaneously pulling the start cord.
- drop zonepredetermined area where cut branches or wood sections will be dropped or lowered from a tree (see landing zone).
- droughtperiod of unusually low precipitation.
- DRTacronym for double rope technique. Climbing system in which two separate ropes and two separate anchor points are utilized (contrast with DdRT and SRT).
- drum lacemethod of tying the root ball of a balled-and-burlapped tree for moving.
- drupestony seed inside a fleshy covering (for example. cherry and peach).
- dry season dormancydrought adaptation of acclimated plants that become dormant during the dry season.
- dshdiameter at standard height
- DWdeadwood
- dynamic cable systemany of several cabling systems that utilize elastic materials (usually rope of various constructions) for tree support systems.
- dynamic loadforces created by a moving load. Load that changes with time and motion (contrast with static load).
- dynamicsstudy of how objects move under the action of forces (contrast with statics).
- dynamometerinstrument for measuring mechanical force or power.
e
- EABemerald ash borer
- EACEuropean Arboricultural Council
- early-successional plant communitiesplant communities that first develop following disturbance. Succession is the replacement of one plant community by another.
- earth augersee soil auger.
- easementlegal. non-possessory interest in real property that conveys use or partial use. but not ownership. of all. or more typically a portion. of an owner's property.
- ECeElectrical conductivity of a soil extract. a physical quantity that measures the readiness with which a medium transmits electricity
- ecologythe study of the relationships between organisms and other living and non-living elements of their environment. economic threshold
- economic benefitsgoods or services provided by the urban forest that increase monetary value of property.
- ecosystemcomplex system of living organisms and their abiotic environment.
- ecotypeLocally adapted variant of an organism. differing genetically from other ceotypes
- ectomycorrhizaetype of mycorrhizae that grow between the cortical or epidermal cells of absorbing roots. forming an outer sheath around the root (see mycorrhizae; contrast with endomycorrlzizae).
- ECwElectrical conductivity of water. a physical quantity that measures the readiness with which a medium transmits electricity
- edema (oedema)watery swelling in plant tissue.
- EElEdison Electric Institute
- effluentWaste material such as liquid industrial refuse or sewage that is discharged into the environment
- EHAPelectrical hazard awareness program
- EHSextra-high strength; extra-heavy standard
- EHS cablesee extra-high-strength cable.
- Elaeocarpus hainanensisHainan Elaeocarpus
- electric supply linesin an electric utility system. conductors used to transmit or distribute electric energy and their necessary supporting or containing structures (see conductor; contrast with distribution lines and transmission lines).
- electric utilityI) corporation. person. agency. authority. or other legal entity aligned with distribution facilities for delivering electricity to consumers. 2) the system of facilities maintained by an electric utility to carry out its operation.
- electrical conductivity (EC)A physical quantity that measures the readiness with which a medium transmits electricity
- electrical conductor1) in an electric utility system. metal wires. cables. and other system components used for carrying electric current. Conductors may be solid or stranded (i.e.. built up by an assembly of smaller solid conductors). 2) any object. material. or medium (e.g.. guy wires. communication cables. tools. equipment. vehicles. humans. animals) capable of conducting electricity if energized. intentionally or unintentionally.
- electrical currentamount of electricity passing through an electrical conductor. Measured in amperes (amps).
- electrical potentialdifference in electric energy between an energized conductor. another energized conductor. the ground or other object. Measured in volts.
- electrical resistancerelative opposition of an object. material. or medium to the flow of electrical current. Measured in ohms. Material such as copper has low resistance and is. therefore. a good conductor; material such as glass has high resistance and is therefore a good insulator (see ohm).
- elevating work platform (EWP)aerial platforms used on work sites in place of ladders and tower scaffolds.
- embolismair bubbles in the xylem typically entering during periods of drought or injury.
- embryorudimentary plant in the seed before it starts a period of rapid growth.
- emergence holesholes in the bark created by insects leaving the plant to complete their life cycle. Also ~ called exit holes.
- emergency responsepredetermined set of procedures ~ by which emergency situations are assessed and handled.
- endline looploop created in the end of a rope by ] forming any of numerous termination knots.
- endomycorrhizaetype of mycorrhizae that grow within root cells (see mycorrhizae; contrast with ectomycorrhizae).
- energized conductorconductor through which electrical current is flowing. This may be intended and expected or the unintended and unexpected result of an electrical short.
- energyin physics. the potential to do work.
- engineered fillmaterial used as a construction base that is different from the surrounding soil profile and has a known compaction rate or load-bearing capacity.
- entireterm describing a leaf margin without teeth.
- environmental benefitsimprovements to the natural world (e.g.. air and water quality) provided by the urban forest.
- environmental impact report (EIR)a document used in planning and development that describes the existing environmental conditions within a property. the significant environmental effects of a project (impacts) . possible ways to minimize significant effects (mitigation). and reasonable alternatives to the project. Contrast with negative declaration.
- EPAEnvironmental Protection Agency
- epicormicShoots that arise from latent or adventitious buds; may occur on branches. stems. or from basal suckers
- epicormic shootshoot arising from a dormant bud. or from newly formed adventitious tissue.
- epidermisouter tissue of leaves. stems. roots. flowers. and seeds.
- epinastydownward curling of the leaf blade. Often a symptom of plant disease. Distortion of growth. often caused by certain types of herbicides.
- epiphytenonparasitic plant that uses another plant as a host for mechanical support. but does not derive nutrients or water from it (contrast with parasite and saprophyte).
- Epipremnum pinnatumEpipremnum pinnatum
- eradicationtotal removal of a species from a particular area. May refer to pathogens or insect pests or to unwanted plants.
- eriophyid mitesmites in the family Eriophyidae. Often even smaller that other mites and requiring higher magnification to see. Often associated with leaf galls (see mites).
- erosionthe wearing away of the land by the movement of water. wind. or ice.
- Erythrina variegataCoral Tree
- escape routein felling operations. direction for chain saw operator to move while tree is falling. Generally 45 degrees on either side of a line drawn opposite the intended direction of fall.
- ESPexchangeable sodium percentage
- espalier1) n. specialized technique of pruning and training plants to grow within a plane. such as along a wall or a fence. 2) n. a plant trained in that manner. 3) v. to train plants in that manner.
- essential elementsminerals essential to the growth and development of trees. These minerals are essential because plants cannot complete their life cycle without them (see macronutrient. micronutrient. and primary elements).
- establishto grow. or cause a plant to grow. successfully in a new place. In forestry. may refer to initial planting and care; in landscaping. may refer to care after planting until the plant is growing successfully.
- ETCCEuropean Tree Climbing Championship
- ethephonplant growth regulator used to promote fruit ripening. Also stimulates latex flow in rubber trees.
- ethylenegaseous plant hormone that triggers fruit ripening and plant senescence.