Forestry 280: Hand lens cross-sections,Woods 1-13: Softwoods with normal resin canals

Views are presented to approximate observation with a 10x hand lens. Thus, both specimen imperfections and some lack of detail will be evident.

Images with species name shown in white are courtesy of the USDA Forest Service, Center for Wood Anatomy Research.

#1 – Sugar Pine, Pinus lambertiana

Normal, longitudinal resin canals

Horizontal

Resin canal

#1 – Sugar Pine, Pinus lambertiana Note the following:

Four normal, longitudinal resin canals

One normal, horizontal (or transverse) resin canal

Wood texture (“medium-coarse”)

Approximately 20x

One growth ring Earlywood

Latewood

#2 - White pineEastern, Pinus strobusWestern, P. monticola

#2 - White pineEastern, Pinus strobusor Western, P. monticola

Approximately 10x

Approximately 20x

Note “honeycomb” appearance of tracheids

# 3 – Lodgepole pine, Pinus contorta

Here, resin canals look like whitish spots.

Note “dimples” on split tangential surface, as seen in large display sample in the classroom!

#4 – Southern Yellow Pines, Pinus spp.

10x

20x

Note frequency of resin canals and prominence of latewood; also, variable wood structure (growth rate, percent latewood, etc.)

#5 – Ponderosa pine, Pinus ponderosa

Resin canals are frequent, numerous; typically present in every growth ring (typical of pines in general).

#5 – Ponderosa pine, Pinus ponderosa

Note “artifacts” (knife marks)

Horizontal resin canal

#6 – Red pine, Pinus resinosa

Resin canals are numerous, but small.

#7 - Jack Pine, Pinus banksiana Don’t separate red

and jack pines macroscopically

Note: These may be separated microscopically: Red pine has window-like cross-field pits; jack pine has pinoid pits. Resin canals

#8 - Tamarack, Larix laricina

10x

20x

Resin canals are small and sparse, appearing here as whitish dots.

#9 – Western larch, Larix occidentalis

Small, sparse resin canals.

#10 – Eastern spruces, Picea spp.

Resin canals small, sparse; often appear as whitish flecks.

#11 – Engelmann spruce, Picea engelmannii

Don’t separate Eastern spruces from Engelmann.Wood is soft, relatively easy to cut, and “lustrous” in appearance.

#12 – Sitka spruce, Picea sitchensis

Sitka has a “purplish” cast in the color of heartwood.

Resin canals sparse; somewhat larger than other spruces.

DO try to separate this from #10 & #11.

This particular sample has indented growth rings, called “bear scratches.”

#13 – Douglas fir, Pseudotsuga menziesii

Small, sparse resin canals.Relatively coarse texture.

#13 – Douglas fir, Pseudotsuga menziesii Heartwood is often

reddish- to orange-red

Heartwood often has a distinctive odor

Resin canals sometimes in short, tangential groups.