Conifers refers to trees like pines, firs, cedars, and hemlocks, that usually have cones and are wind pollinated. In our area they are evergreens.
The main conifers on the Westside trail are the pines. Pines have bundles (fascicles) of needles. They tend to have larger cones than most conifers. There are three species of pines on the trail, two with 3 needles, and one with 5 needles per bundle.
Foothill, or gray pine, (Pinus sabiniana) is the most common pine at this elevation. It is very distinctive, with a rounded top, somewhat gray needles, and very large cones with very sturdy protuberances called umbos. Unlike most pines, there are usually several stems that go up to the canopy instead of a main central stem or trunk. The large cones have relatively large seeds, large enough to use as pine nuts. The cones may remain on the tree for a number of years. Squirrels sometimes cut them down and tear or chew them apart to get those seeds.
Ponderosa pine (Pinus ponderosa) also grows along the trail in the cooler areas. They have green needles in bundles of 3, a single main stem, and smaller cones. The umbos on the cones point out, so they are sometimes called “prickly ponderosa” as opposed to “gentle Jeff” for the fairly similar Jeffrey pines that grow up higher.
Sugar pine (Pinus lambertiana) is the final pine. It has bundles of 5 needles and and the needles are shorter than the other two pines. Sugar pine is part of the white pine group, which is vulnerable to white pine blister rust. It has very large branches with very long cones at the end of them. It usually grows up at higher elevations but there are small sugar pines down near the river where it is cooler and moister than where the trail is higher on the slope.
Incense cedar (Calocedrus decurrens)- There are a lot of different groups of trees called “cedars.” This one has scaly leaves that are pressed up against the branches. The branches form flat sprays. The bark on large trees is soft and thick, protecting the trees from fire, but the young trees burn easily. The cones are very distinctive. I have only seen saplings on the trail but there are trees down by the river
A final conifer observed on the trail is Douglas-fir (Pseudotsuga menziesii). There is one young tree near the second washout and one stressed and yellowed sapling and it is yellowed by the trail. These trees usually grow up much higher and are mainly on the north facing slopes where it is cooler and more moist.
Douglas-fir is hyphenated because it is not a true fir. It can be hard to tell Douglas-fir from white fir. One key is that the true firs have rounded buds and Douglas-fir has pointy buds. The cones of the Douglas fir stay intact and the cones of the true firs fall apart on the tree to release the seeds.
I have not seen white fir (Abies concolor). I mention it here because it can often grow in the same conditions where these conifers grow. White firs have single needles that spiral around the branch. As they get older, they are arranged so they appear to come out of the two sides of a twig. As a true fir, cones are held upright with closely packed scales. The scales of the cones fall apart on the tree releasing the seeds to helicopter away.
Both white fir and incense cedar can grow in under other trees. There tend to be more of them when fire, which would normally kill many of the small trees, is prevented. The pines grow in open areas, and unlike firs and cedars, do not grow well in shade.
Diving Deeper This is a section for more information on some aspects of these trees not related to identification..
The difference in the form of foothill pine compared to other conifers mentioned here is due to apical dominance. In the other conifers, the apical (top) bud produces a plant hormone, auxin, that inhibits the grow of the buds on the side-branches. The closer the buds are to the tip of the tree, the more they are inhibited. The foothill pine has weak apical dominance, so it often has several main stems or trunks instead of a single trunk and a conical shape typical of most conifers.
The foothill pine generally grows at lower elevations than the other conifers mentioned here. It is adapted for fire by having serotinous cones. The cones are stuck together with pitch and usually stay closed on the tree until there is a fire or the tree dies. Then they are released to grow in the now open soil. The cones you may see along the trail have likely be chewed off by squirrels in order to get the pine seeds. Trees with normal cones drop cones or seeds every year.
Reproduction strategies of trees Trees produce a lot of pollen and a lot of seeds. Yet over their entire lifetimes, they only need to have one of those seeds over their entire lifetime establish and mature in order to reproduce successfully. If there is good unoccupied habitat, many seedlings may establish. In times of changing climate, such as after the last glaciation, the seed production helped them to slowly move north again. Species with a soft sweet covering of the seeds that birds eat (such as elderberry) may travel faster than those with wind distributed seeds, because the birds may fly larger distances before releasing the seeds in their droppings.
In addition, the seedlings of some trees do better growing in the shade of other trees while other trees, such as ponderosa pine, need large open areas for seedlings to grow. So seedlings may not establish when conditions are not favorable in the area.
Other pine trees on this forest
Pines are grouped by the number of needles in each fascicle (bundle).
1 needle Pinyon pine (Pinus monophylla) These mostly grow east of the Sierra crest, but at least one has made it to this side!
2 needle Lodgepole pine (Pinus contorta ssp. muricata) at higher elevations and near meadows.
3 needle
- Knobcone pine (Pinus attenuata) at lower elevations
- Jeffrey pine (Pinus jeffreyi) at higher and drier sites.
- Ponderosa pine and gray pine are found on the trail
5 needle (White Pines)
- Whitebark pine (Pinus albicaulis) is found near timberline.
- Western white pine (Pinus monticola) also found at high elevations
- Sugar pine is found on the trail.
White pines, such as sugar pine, can be killed by white pine blister rust. The rust is caused by a non-native fungus (Cronartium ribicola), that was introduced in the 1900s from Asia. After a tree is infected with the rust, some of its branches die (flagging). Then the whole tree dies. Besides a white pine, the rust needs another plant to complete its life cycle. Usually that plant is wild currents or gooseberries (Ribes), but Indian paintbrush (Castilleja) and wild snapdragon (Pedicularis) can also be hosts.
Locally, there is a program for growing rust resistant sugar pines. If you see metal bands around trees in the forest, those are trees that may be resistant to the blister rust. The bands keep the squirrels from climbing the trees so the seed can be harvested to grow rust resistant trees.
For more information see: https://www.fs.fed.us/rm/highelevationwhitepines/Threats/blister-rust-threat.htm