General Features of the Tree

• General Features
• Bark
• Indumentum on Branches

General Features

Habit

Emergent trees - Trees that noticeably extend beyond the canopy of the forest Large trees - Trees that make up the canopy of the forest. Small trees - Sub-canopy sized trees

Trunk shape (in section)

cylindrical (or sub-cylindrical) in cross-section	markedly fluted in cross-section

Trunk shape (lengthwise)

straight (or only very slightly crooked)	(markedly) crooked

Buttresses

This feature is recorded as either: present absent

Spines

It is recorded as either: present absent

Spines (position)

Whether the spines occur: on the trunk on the branches

Aerial roots

The aerial roots are recorded as either: present absent

Stilt roots

Stilt roots are either recorded as: present absent

Terminal buds

The terminal developing buds are recorded as either: enclosed, or not enclosed

Bark

Bark (outer - colour)

The colour types include: white cream yellow green orange red grey brown black

Note: a mixture if these colour types are frequently present.

Bark roughness

rough The surface of the bark should be rough to touch and may vary from finely to coarsely rough	smooth Frequently, trees that have smooth bark may also be slightly flakey (as in the species illustrated here). However, if the majority of the surface of the bark is smooth to touch, then it is recorded as 'smooth'.

Bark texture

scaly or flaky Since these two type of bark roughness are sometimes difficult to distinguish from each other, both categories are here grouped together. Flaky bark (eg. Heritiera trifoliolata) consists of many regular to subregular, thin flakes. Scaly bark (eg. Mangifera minor) is structurally similar, but usually thinner and not as regular as the flakes of the former example. Artocarpus vriesiana has scaly or flaky bark.	fissured Fissured bark is finely split into many narrow grooves (eg. Dysoxylum inopinatum)
peeling The bark splits or crack and then falls away in thin patches, sheets or long ribbons. The surface of the bark underneath the peeling layer is usually very smooth (eg Eucalyptus deglupta)	cracked The outer surface of the bark is more or less smooth but it is divided into irregular plate-like areas by relatively broad cracks
furrowed cork Bark with relatively long narrow depressions or grooves (eg. bark of the introduced Pinus caribaea)	pustular The bark is more or less covered with raised, rough, irregular bumps or lines of pustules/lenticels. In between the pustules, the surface of the bark is usually smooth or almost smooth (eg. Alstonia scholaris)
tessellated The outer bark is finely divided into more or less regular square-like pieces so that it has a 'chequered' appearance. Note: the pieces do not detach readily (eg. Rhus taitensis).	pitted The bark usually has small sunken pits with the general surface of the bark more or less smooth (eg. Dracontomelum lenticulatum)

Bark lenticels (pustules)

elongated laterally The lenticels are arranged laterally across the trunk forming a raised more or less horizontal lines of pustules	elongated vertically Lenticels are arranged vertically alon the trunk forming a raised more or less vertical lines of pustules
rounded/swellings Lenticels more or less form globular (rounded) raised swellings on the surface (eg.Alstonia scholaris)	irregular Lenticels do not form any of the above arrangements as they are irregular in shape and orientation

Bark subrhytidome colour

The colour types include: white yellow orange green red brown black mottled

Bark thickness type

This feature includes the total bark thickness, that is, both outer and inner bark

This feature records whether the bark is thick or thin: <25 mm thick (namely, less than 25 mm thick; hence, thin) >25 mm thick (namely, greater than 25 mm thick; hence, thick)

This standard for differentiating between thick and thin bark, as used in Australia,
has proved to be less useful in Papua New Guinea. It has been found that most
Papua New Guinean trees have thin bark, based on this classification system.
Although this feature is still included in this first version of the Guide to Trees of Papua New Guinea,
it will either be redefined or replaced by the following bark thickness measurement (mm)
feature in future versions.

Bark thickness measurement (mm)

Bark blaze layering

one layer	two layer Note: both an inner and outer layer can be distinguished. The layers are most commonly identified by differences in colour

Bark blaze aroma

The bark is either: faintly to non-aromatic, or strongly aromatic

Note: Since the aroma of the bark is frequently only fully developed in mature trees,
it is recommended that caution be used when attempting to categorise the aroma of
bark on trees with a trunk of less than 50 cm in diameter at breast height (dbh)
(approximately 1.3 m above ground).

Bark blaze aromatic type

Note: this feature is relatively subjective since the recognition of different aromas
are dependent on the individual. Therefore, this character should be used with caution.
The two general categories, pleasant and unpleasant have been included
when it is difficult to determine which of the other categories best describe the odour.
Please note that the above descriptors are not mutually exclusive.

Bark outer blaze colour

The colours of the outer blaze that are recognised include: white yellow orange pink red brown black green mixed colours grey

Note: the category mixed colours is used when several (usually more than 2) different colours are present

Bark outer blaze markings

markings absent	speckled - marking more or less as wide as long, hence like dots	with stripes - markings distinctly longer than wide, hence like lines

Bark outer blaze texture

smooth - hence, lacking any texture	fibrous - texture consisting of long fibrous groupings of cells
granular with splinters - bark crumbling into small blocks of cells with long splinter-like pieces of bark amongst granules	granular without splinters - all the outer bark crumbles into small blocks of cells. The long splinter-like pieces of bark are absent from this layer
corky - very light, more or less smooth bark, frequently relatively thick, similar in texture to corks used in bottles

Bark inner blaze colour

The colours of the inner blaze that are recognised include: white yellow orange pink red brown black green mixed colours grey

Note: the category mixed colours is used when several (usually more than 2) different colours are present.

Bark inner blaze markings

This feature records the presence or absence of marking in the inner bark blaze
The values include:

markings absent	speckled - marking more or less as wide as long, hence like dots	with stripes - markings distinctly longer than wide, hence like lines

Bark inner blaze texture

This feature records the texture of the barks inner blaze. The texture can be one of the following categories:

smooth - hence, lacking any texture	fibrous - texture consisting of long fibrous groupings of cells
granular with splinters - bark crumbling into small blocks of cells with long splinter-like pieces of bark amongst granules	granular without splinters - all the inner bark crumbles into small blocks of cells. The long splinter-like pieces of bark are absent from this layer
corky - very light, more or less smooth bark, frequently relatively thick, similar in texture to corks used in bottles

Bark exudate (sap) presence

This feature records the presence or absence of bark exudate (sap). The presence of this feature
is observed after the bark is cut through to the outer wood. Since the sap often takes a few moments
to appear after the bark is cut, wait a minute or two before deciding that sap is absent. When sap is
not abundant it frequently does not appear immediately.

This feature is recorded as either: present, or absent

Bark exudate (sap) colour

When the bark exudate (sap) is present, this feature records the colour of the sap
when first exposed to the air by the cut.

The following colours are recognised: white/milky yellow red brown colourless (lacking colour/clear, often watery) green blue

Since the colour of the sap may change rapidly once exposed to the air by the cut,
the sap colour should be recorded immediately.

Bark exudate (sap) abundance

When the bark exudate (sap) is present, this feature records
abundance of the sap when the bark is cut. The sap is recorded as:

flowing- Soon after the blaze is cut, the exudate/sap flows abundantly	spotty, not readily flowing- The exudate/sap usually takes awhile to appear, but even when it appears immediately, it does not readily flow (hence referred to as spotty)

Bark exudate (sap) colour changing

When the bark exudate (sap) is present, this feature records
if the colour of the sap changes when the bark is cut.

The two values of this feature are: colour changing on exposure to air, or colour not changing on exposure to air

Note: the sap frequently becomes slight darker, but this is not regarded as a colour change

Bark exudate (sap) colour change

When the bark exudate (sap) is present and the colour of the sap changes when the bark is cut,
this feature records the final colour of the sap.

The following colours are recognised: grey orange brown black golden-coloured red green

Bark exudate (sap) stickiness

When the bark exudate (sap) is present, this feature records if the exudate is:

sticky when touched, or not sticky.

Indumentum on Branches

Complex hairs (presence)

This feature records the presence or absence of complex (not simple) indumentum.
The indumentum either consists of variously branched hairs or trichomes that have
been modified into scales. Since these complex hairs are usually very small, a 10X hand lens
or a microscope is required for viewing these features.

Complex hairs are recorded as either: present or, absent

Complex hairs (type)

When complex hairs are present, then this character records the type of complex hairs present.
Note: A 10X hand lens or microscope is required for viewing the details of these features.
The types of complex hairs recorded include:

Disk-shaped - (peltate) the axis of the hair terminating in a more or less flattened disk of tissue, with the axis attached to the centre of the disk	Star-like - (stellate) the hair is once-branched with each branch radiating out from a single point	T-shaped - the hair terminates in two branches that approximately at right angles to the hairs axis
Club-shaped - the hairs are swollen towards the apex of the hair such that the hair appears obovoid.	Head-like - (capitate) the hairs terminate in a small more or less globular swelling	Awl-like - the hairs are narrow and gradually tapering to a fine point

Stinging hairs

This feature records the presence or absence of stinging (urticating) hairs anywhere
on the tree. Typically, these hairs are found in certain species of the Family Urticaceae
(for example, Dendrocnide species).

Stinging hairs are recorded as either: present or, absent

Mature twig indumentum (hairs) presence

This feature records the presence or absence of hairs on the twigs
which are the smallest distal branchlets.

Indumentum (hairs) are recorded as either: present or, absent on the mature twigs.

Mature twig indumentum (hairs) density

When hairs are present on mature twigs, this feature records
the density of these hairs as either:

dense, or sparse

Note: This feature is often best observed through a 10X hand lens.
When the indumentum is dense, the hairs are usually easily observed,
even when the hairs are short. However, when the indumentum is sparse,
the hairs may sometimes be difficult to see.

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