The crown of a plant is the total of an individual plant's aboveground parts, including stems,

leaves A leaf (: leaves) is a principal appendage of the stem of a vascular plant, usually borne laterally above ground and specialized for photosynthesis. Leaves are collectively called foliage, as in "autumn foliage", while the leaves, stem, ...

, and reproductive structures. A

plant community A plant community is a collection or Association (ecology), association of plant species within a designated geographical unit, which forms a relatively uniform patch, distinguishable from neighboring patches of different vegetation types. The comp ...

canopy consists of one or more plant crowns growing in a given area. The crown of a

woody plant A woody plant is a plant that produces wood as its structural tissue and thus has a hard stem. In cold climates, woody plants further survive winter or dry season above ground, as opposed to Herbaceous plant, herbaceous plants that die back to t ...

(

tree In botany, a tree is a perennial plant with an elongated stem, or trunk, usually supporting branches and leaves. In some usages, the definition of a tree may be narrower, e.g., including only woody plants with secondary growth, only ...

shrub A shrub or bush is a small to medium-sized perennial woody plant. Unlike herbaceous plants, shrubs have persistent woody stems above the ground. Shrubs can be either deciduous or evergreen. They are distinguished from trees by their multiple ...

liana A liana is a long-Plant stem, stemmed Woody plant, woody vine that is rooted in the soil at ground level and uses trees, as well as other means of vertical support, to climb up to the Canopy (biology), canopy in search of direct sunlight. T ...

) is the

branch A branch, also called a ramus in botany, is a stem that grows off from another stem, or when structures like veins in leaves are divided into smaller veins. History and etymology In Old English, there are numerous words for branch, includ ...

es,

, and reproductive structures extending from the trunk or main stems. Shapes of crowns are highly variable. The major types for trees are the excurrent branching habit resulting in conoid shapes and decurrent (deliquescent) branching habit, resulting in round shapes. Crowns are also characterized by their width, depth, surface area, volume, and density. Measurements of crowns are important in quantifying and qualifying plant health, growth stage, and efficiency. Major functions of the crown include light energy assimilation, carbon dioxide absorption and release of oxygen via

photosynthesis Photosynthesis ( ) is a system of biological processes by which photosynthetic organisms, such as most plants, algae, and cyanobacteria, convert light energy, typically from sunlight, into the chemical energy necessary to fuel their metabo ...

, energy release by respiration, and movement of water to the atmosphere by

transpiration Transpiration is the process of water movement through a plant and its evaporation from aerial parts, such as leaves, stems and flowers. It is a passive process that requires no energy expense by the plant. Transpiration also cools plants, c ...

. These functions are performed by the leaves.

Crown classes

Trees can be described as fitting different crown classes. Commonly used are Kraft's classes. Kraft designated these "social classes" based on temperate and boreal forests in

Central Europe Central Europe is a geographical region of Europe between Eastern Europe, Eastern, Southern Europe, Southern, Western Europe, Western and Northern Europe, Northern Europe. Central Europe is known for its cultural diversity; however, countries in ...

, so they do not necessarily work with every forest type in the world. Kraft wrote in German so here are his classes with translations: * 1 v vorherrschend (predominant) * 2 h herrschend (dominant) * 3 m mitherrschend (co-dominant) * 4 b beherrscht (dominated / suppressed) * 5 u unterständig (inferior) this is then split into 2 subclasses 5a (shade tolerant trees) and 5b (dying crowns / dying trees) Often it has been simplified to Dominant, Co-dominant and Suppressed. Also IUFRO developed a tree classification it is based on three components with numbers that then aggregate to give a coded classification thus: Ecological criteria Height component (Stand layer / Height class): * 100 Overstorey / Overlayer * 200 Middlestorey / Middlelayer * 300 Understorey / Underlayer Vitality component (Tree vigor / vitality): * 10 Lush * 20 Normal * 30 Retarded Future growth potential component (Developmental tendency / conversion tendency): * 1 High * 2 Average * 3 Lagging and then additionally Silvicultural criteria Commercial worth * 400 Valuable, outstanding tree * 500 Usable, wood * 600 Poor to Unusable Quality Trunk class * 40 Valuable wood (≥50% of the trunk is high-quality timber) * 50 Normal wood (≥50% of the trunk is normal-quality timber) * 60 Substandard wood (<50% of the trunk is normal-quality timber) Crown class * 4 Deep crown (>½ the tree length) * 5 Medium crown * 6 Shallow crown (<¼ the tree length) While both Kraft and IUFRO classifications are aimed at describing individual tree crowns both can and are applied to describe whole layers or storeys.National Forest Inventories: Contributions to Forest Biodiversity Assessments Gherardo Chirici, Susanne Winter, Ronald E. McRoberts Springer Science & Business Media, 2011 - 206pp

References

External links

Tree crown
{{Authority control Plant morphology

Crown classes

See also

References

Further reading

External links