Introduction to Dendrology

Dendrology is the study and identification of woody plants, especially trees, shrubs, and woody vines. This introductory sheet combines field identification with basic wood anatomy and ecological interpretation. Identify a plant from several independent characters rather than one leaf or a common name.

Begin with the whole plant and its setting

Record growth form, branching, approximate size, location, habitat, and season. A tree in a planted landscape may be far outside its natural range. Habitat can support an identification but cannot replace diagnostic characters.

Use the accepted scientific name to connect observations with references. Cultivars, hybrids, juvenile foliage, and damaged shoots may differ from a field guide’s typical illustration.

Use a repeatable sequence of characters

Character	What to record	Common trap
Leaf arrangement	Alternate, opposite, or whorled along the twig.	Mistaking opposite leaflets for opposite leaves.
Leaf construction	Simple or compound; leaflet number and attachment.	A true leaf has an axillary bud at its base; a leaflet does not.
Margin and veins	Entire, toothed, or lobed; vein arrangement.	Relying on one unusually shaped leaf.
Twig and buds	Bud position, scales, scars, hairs, pith, and thorns.	Ignoring winter characters when leaves are absent.
Bark	Color, texture, lenticels, plates, or furrows.	Young and old bark can look very different.
Flowers fruits or cones	Structure, arrangement, size, and season.	Identifying from a fallen fruit that came from a neighboring plant.

Wood is part of a transport and support system

The vascular cambium produces secondary xylem toward the inside and secondary phloem toward the outside. Xylem carries water and dissolved minerals and provides support. Phloem transports sugars and other substances between sources and sinks. Outer protective tissues form part of the bark.

Sapwood includes functioning water-conducting tissue. Heartwood is older inner wood that no longer serves the same conducting role. The proportion varies by species and age. A tree can have internal decay while retaining living tissue around the outside.

Growth rings can preserve evidence of seasonal growth, but ring visibility and the relationship between rings and years vary. Do not assume that every tropical tree produces one clear annual ring.

Ecology explains where a woody plant succeeds

Compare tolerance of shade, drought, flooding, cold, and soil chemistry. Consider how roots, buds, leaves, and reproductive structures respond to disturbance. A species suited to a floodplain may fail in a compacted, drought-prone planting pit.

For a Lafayette native-plant claim, verify the exact species against county-level occurrence evidence. A species native somewhere in Indiana is not automatically documented as native in Tippecanoe County. Horticultural presence is also not proof of natural occurrence.

A useful field record supports later verification

Photograph the whole plant, a twig with buds, both leaf surfaces, bark, and attached reproductive structures. Include scale and date. Record the proposed name, evidence supporting it, and the strongest look-alike. Avoid stripping bark or cutting large branches simply to obtain identification material.

A dichotomous key narrows alternatives through paired choices. Read both choices at each step and check the final description. If essential characters are missing, leave the identification at genus or family rather than forcing a species name.