### substance | wood:

Hardwood
* Most hardwoods produce dramatic leaf coloration if climatic conditions are favorable
  - sprout profusely from roots and stems when the tree is cut or placed under stress.
  * ' is wood from deciduous trees and broad-leaf evergreen trees. Hardwoods all have enclosed nuts or seeds. Hardwood is in contrast to softwood which come from conifers, cone bearing seed plants. Hardwoods are not always harder than softwoods, Balsa wood being a notable exception. Hardwoods have a more complex internal structure than softwoods. Softwoods have a structure that looks like many drinking straws bound together all of which are used to supply water to the tree. Hardwood trees are more varied than softwoods and there are about 100 times more species of hardwood than there are softwoods
* also have the ability to naturally seed themselves or sprout from roots from cut trees.
* are Pennsylvania's most renewable resource
  - a type of tree that produce a dense wood
* are also an integral component of the higher elevation mixed coniferous forests
  - less likely to decay or rot than softwoods
  - at a disadvantage in the winter, as well
  - broad-leaf trees that lose all of their leaves at one time, usually in the fall
  - deciduous, meaning they lose their leaves each fall
  - hand-polished to bring out their rich, unique characteristics
  - in many ways easier to use than pine
  - porous and readily absorb and release moisture, oil, bacteria, etc
  - produced by angiosperm trees that reproduce by flowers, and have broad leaves
  - the trees that have broad leaves, while softwoods are the needled or conifer trees
* burn clean and slowly and leave lots of good hot cooking coals
  - slower and longer
* come from deciduous trees.
* comprise the majority of the forest, with oak and hickory predominating.
* contain more energy per cubic metre than softwoods because they are usually denser.
* dominate as do black bears.
* follow the major drainage systems from east to west.
* generally come from broadleaf trees that lose their leaves in winter.
* grow slower than softwoods.
* have a denser structure, which is the reason they are usually harder and heavier
  - dormant buds along their entire length that can become active and sprout
  - less creosote build-up than softwoods
  - thin bark that is easily damaged by fire
  - tracheids, vessels, fibers, ray tracheids, and xylem parenchyma
* make better firewood than do soft woods
  - up the great bulk of harvested timber
* normally have broad leaves and come from deciduous or broad-leafed evergreen trees.
* populate the rich bottom lands of the valleys, and pines predominate on poorer lands.
* possess 'vessels or 'pores' in their ring structure to carry sap up the trunk.
* predominate the regenerative species.
* produce less smoke and thus a lighter gray color.
* provide a longer lasting fire and are best used after preheating the chimney.
* take longer to dry than softwoods.
* usually have vascular tracheids as well as vessels and fibres.
* vary in their active growth cycle, which generally equals the amount of time they die.
+ Hardwood, Introduction: Wood
  * Hardwoods are a type of tree that produce a dense wood. Unlike softwoods, hardwoods usually have broad leaves. Except for brown, these colours are always present in the leaves while they are green but are masked by the large amounts of chlorophyll which is green. In a green leaf, water drawn up from the ground, carbon dioxide from the air and sunlight combine with water to make molecules of glucose which the tree uses as energy to grow. In some cases such as the maple trees glucose gets trapped inside the autumn leaf and sunlight and cool weather turns the glucose into reds and purples. The brown colours seen in autumn leaves are due to waste products left inside the leaf
  - Properties
  * Each species of hardwood has its own set of properties, however they have some properties in common. Hardwoods normally have broad leaves and come from deciduous or broad-leafed evergreen trees. Hardwoods grow slower than softwoods. Evergreen softwoods grow faster than deciduous hardwoods, and can grow to a larger size. Hardwoods are excellent for carving. One of the hardest hardwoods is black ironwood which is recognized by the Guinness Book of World Records as the heaviest wood. Ironwoods are so dense that they sink in water rather than float as other woods do.
  * The properties of the wood are caused by its structure. Hardwoods have a denser structure, which is the reason they are usually harder and heavier. Hardwood has xylem vessels which are used to transport water. The quantity of lignin is probably the main factor in their hardness
  - Uses of hardwood
  * Hardwoods are often used to make items that get used a lot because of their density. These items include furniture, flooring, and utensils. They are also used in construction. Hardwoods are also less likely to decay or rot than softwoods. Furniture made by hardwood joinery is more expensive than that made from softwoods. Utensils for use in preparing food can include things such as the vessel in the gallery below used by the Ede people to grind corn and grains for food. Because of the dense nature of the wood used such a vessel can be used for many years without breaking. Other examples include the handle of the Luzon knife seen in the gallery. Because of the nature of sound transmission provide a good wood for musical instruments such as violins, guitars, pianos and hand drums such as the Djembe drum pictured in the gallery below