Arboriculture Glossary of Terms
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- habitcharacteristic form or manner of growth.
- habitatan environment suitable for sustaining a population of a given organism.
- half hitchknot used to temporarily attach a line to l an object. Also used as a backup in combination with other knots.
- halophytesplants that tolerate soils with a high concentration of salts.
- hand lensa small. handheld magnifying glass; a Ioupe.
- hand pruning shearstool used for pruning twigs and small branches less than 1/2 inch (1.27 mm) diameter (see secateurs).
- hangerbroken or cut branch that is hanging in a tree.
- hard hatprotective hat made of a rigid material. usually without a chinstrap. that must be worn when performing l ground operations. A form of personal protective equipment (PPE) (contrast with climbing helmet).
- hard lay roperope manufactured with tightly wound strands. making it stiffer than standard lay or soft lay ropes.
- hardened off1) plant tissue that is acclimated to the cold or a new environment. 2) a process that acclimates balled and burlapped trees to water stress when dug with foliage.
- hardening-offOne of several forms of acclimation associated with either decreasing temperatures (increasing tolerance to low temperature) or the transition from nursery environment to the landscape
- hardinessgenetically determined ability of a plant to survive low temperatures.
- hardpancompacted soil layer nearly impervious to water. air. and roots.
- hardscapethe constructed elements of a landscape. such as walls. pathways. and seats made of wood. stone. and/or other materials.
- hardwoodI) wood of an angiosperm tree as distinguished from that of a conifer; broad leaf tree. 2) referring to an angiosperm. or broad leaf tree.
- harnessset of straps and fittings worn for work-positioning when climbing trees (see climbing saddle).
- HASAWAHealth and Safety Work Act
- HAVhand-arm vibration
- Haven gripdevice used to clasp and hold common grade cable (see cable grip; contrast with Chicago grip).
- hazard assessmentsystematic process of identifying hazardous and non-hazardous conditions (see risk assessment).
- hazard mitigationthe process of managing. reducing. or eliminating an identified hazard.
- hazard reduction pruningtype of pruning to remove dead. severely decayed. split. or other branches or tree parts (including fruit or fronds) that pose an elevated level of risk.
- hazard treea tree that has been assessed and found to be likely to fail and cause an unacceptable degree of injury. damage. or disruption. Hazard trees pose a high or extreme risk.
- headingcutting a shoot back to a bud or cutting branches back to buds stub . or lateral branches not large enough to assume apical dominance. Cutting an older branch or stem back to a stub in order to meet a structural objective.
- heading cutcutting a shoot or branch back to a bud. stub. or small lateral branch. Cutting an older branch or stem back to a stub to meet a structural objective.
- healinga physiological. regenerative process not know to occur in plants.
- heartwoodwood that is altered (inward) from sapwood and provides chemical defense against decay causing organisms and continues to provide structural strength to the trunk. Trees may or may not have heartwood (contrast with sapwood).
- heartwood rotany of several types of fungal decay of tree heartwood. often beginning with infected wounds in the living portions of wood tissue. Also called heart rot.
- heat island effectan urban area that is warmer than its surrounding rural areas due to urban activities and greater heat retention by urban structures and development.
- heat toleranceability of a plant to endure high temperatures.
- hedge shearstool used to trim (shear) hedges.
- heeling inmethod of storing bare-root trees by covering roots with sawdust or mulch until ready to plant.
- Heliconia psittacosis Heliconia psittacosis
- herbicideAgent used to destroy or inhibit plant growth. especially on weeds
- herbicidesa pesticide used to kill. slow. or suppress plant growth by interfering with botanical pathways.
- herbivorean animal that feeds primarily on plants.
- Hessiansee burlap.
- HHRhigh hedges regulations
- Hibiscus cooperi Hibiscus cooperi
- Hibiscus schizopetalusHibiscus schizopetalus
- Hibiscus tiliaceusCuban Bast - Sea Hibiscus
- high-voltage linesin an electric utility system. lines with voltages greater than a specified amount depending on the utility.
- hingestrip of uncut wood fibers created between the face cut or notch and the back cut that helps control direction in tree felling or limb removal. Holding wood.
- hinge cutsequence of cuts used to control the direction of a limb being removed.
- hitch1) type of knot made when a rope is secured around an object or its own standing part (contrast with bend). 2) a mechanical device for connecting a towing vehicle to a trailed or towed vehicle or implement.
- HMSH. Muenter system
- holding woodsection of wood located between the face cut and the back cut that helps direct where the tree will fall (see hinge).
- hollow braidrope construction consisting of a braided rope with no core.
- honeydewsugary substance secreted by certain insects. including aphids and some scale insects. when feeding on plants.
- horizonlayer of soil within the soil profile.
- horizontal boringunderground tunneling parallel to grade. performed with special machinery. without an open trench. Alternative for installation of underground utilities that avoids cutting of tree roots or damage to hardscape or existing utilities (contrast with radial trenching. trenching. and tunneling).
- hormonesee plant hormone.
- horticultural oilshighly refined petroleum oils applied to plants to control certain insects and other pests by disrupting their respiration.
- horticulturethe art and science of cultivating ornamental plants. flowers. fruits. and vegetables.
- hostliving organism from which a parasite obtains nutrition.
- HRIHorticultural Research Institute
- HSheavy standard
- HSEin the United Kingdom. the Health and Safety Executive. which is the government agency that deals with health and safety in the workplace.
- Humboldt notchfelling notch that is horizontal on the top and angled on the bottom. Also called Humboldt scarf or reverse scarf (contrast with conventional notch and open-face notch).
- humusdark-colored. stable form of organic matter that remains after most of plant or animal residues have decomposed.
- HVhigh voltage
- hybridplant resulting from a cross between two or more other plants that are more or less alike.
- hydrocarbonorganic chemical compound containing hydrogen and carbon atoms. Hydrocarbons from fossil fuels are linked to pollution and global warming.
- hydrogelscrystalline polymers which absorb water and. if needed. can be added to the soil to increase its water holding capacity.
- hydrophilicthe physical or chemical property of a molecule or substance that is attracted to water (and may be dissolved in water).
- hydrophobicthe physical or chemical property of a molecule or substance that repels water.
- hydrozoninggrouping plants in a landscape according to their water requirements.
- hygroscopicretained water that is held too tightly in soil for uptake by plants.
- Hyphorbe lagenicaulisHyphorbe lagenicaulis