Forestry 280: Hardwood Anatomy Hardwood Anatomical Structure Longitudinal Cells Ray Tissue Distinction from Softwood anatomy Identifying characteristics Forestry 280: Hardwood Anatomy

Forestry 280: Hardwood Anatomy Longitudinal Cells Fibers Vessel Elements Longitudinal Parenchyma Tracheids Forestry 280: Hardwood Anatomy

Forestry 280: Hardwood Anatomy Fibers Fiber Tracheids – long, tapered, thick walled hardwood xylem cells Similar to Softwood Tracheids: Contain bordered pits Secondary thickening of cell wall Forestry 280: Hardwood Anatomy

Forestry 280: Hardwood Anatomy Fibers Distinction from Softwood Tracheids: Shorter in length, 1 – 2 mm Round in cross section Almost solely responsible for strength Libriform fibers – Similar to fiber tracheids except for “apparent simple pits” Forestry 280: Hardwood Anatomy

Forestry 280: Hardwood Anatomy Vessel Elements Vessel Elements – Specialized vertical conducting cells Much larger in diameter than other longitudinal hardwood cells When viewed in cross section commonly termed pores Typically they do not elongate These cells join vertically to form vessels Vessels often stray from straight alignment Forestry 280: Hardwood Anatomy

Forestry 280: Hardwood Anatomy Vessel Elements Wide range of pore diameters 20 – 300 µm Variation often occurs within a growth ring: Ring Porous – Early wood contains large vessels late wood with smaller pores Diffuse Porous – Fairly uniform pore diameter throughout growth rings Semi–ring–porous or semi–diffuse–porous Forestry 280: Hardwood Anatomy

Forestry 280: Hardwood Anatomy Vessel Elements Perforation Plates: Cell divisions that contain unrestricted voids or perforations that allow fluid transport Perforations formed by enzymatic degradation of plates upon maturation of the cells Perforation plate patterns can be use for species identification purposes Forestry 280: Hardwood Anatomy

Forestry 280: Hardwood Anatomy Vessel Elements Vessel Pitting: Vessel to Vessel – Three typical arrangements (below) Vessel to fibers or tracheids – Typically bordered Vessels to parenchyma – Bordered, half-bordered, or simple Forestry 280: Hardwood Anatomy

Forestry 280: Hardwood Anatomy Vessel Elements Tyloses: Outgrowths (or ingrowths!) of parenchyma cell walls into the lumen of adjacent vessel elements Function: Primarily in damaged tissue Protect against moisture loss Prevent the spread of pathogens Act as a barrier in the formation of heartwood Forestry 280: Hardwood Anatomy

Forestry 280: Hardwood Anatomy Vessel Elements Tyloses formation: Enzymatic degradation of pit membranes between parenchyma and vessel elements Outgrowth of parenchyma cell membrane into vessel (Tylosis) Tyloses may remain thin walled or experience secondary thickening Presence of tyloses can affect the utilization of wood Forestry 280: Hardwood Anatomy

Forestry 280: Hardwood Anatomy Longitudinal Parenchyma Parenchyma are thin-walled storage cells May have darkly-stained contents May comprise 1-24% of wood volume (domestic hardwoods); may be up to 50% (some tropical species) Forestry 280: Hardwood Anatomy

Forestry 280: Hardwood Anatomy Longitudinal Parenchyma Axial strand parenchyma – formed by transverse division of fusiform cambial initial Fusiform parenchyma – derived from fusiform cambial initial tapered at both ends, storied arrangement Epithelial cells – surround gum canals or gum ducts, typically traumatic in origin Forestry 280: Hardwood Anatomy

Forestry 280: Hardwood Anatomy Longitudinal Parenchyma Parenchyma Arrangement: Forestry 280: Hardwood Anatomy

Forestry 280: Hardwood Anatomy Hardwood Rays Cell Types – Ray Parenchyma Procumbent – horizontally oriented when viewed in radial plane procumbent = “lying down” rectangular cells in brick-like arrangement typically found at the center of rays Upright – vertically oriented when viewed in radial plane sometimes called square ray cells long axis of cell aligned vertically Forestry 280: Hardwood Anatomy

Forestry 280: Hardwood Anatomy Hardwood Rays Ray types: Homocellular – composed of a single cell type; either procumbent or upright Heterocellular – composed of both procumbent and upright ray parenchyma cells ************** Rays may be narrow (uniseriate), multiseriate, wide “oak-type” (very wide multiseriate rays) or aggregate Forestry 280: Hardwood Anatomy