Like the trees in tropical rain forests, our Sitka spruces serve as habitat for other plants, or epiphytes, living upon them. In tropical areas, the epiphytes are vines and other specialized plants that climb the trunks of the trees, live along the branches, or grow in angles where branches join the trunk. The epiphytes we see here are mostly mosses, forming luxuriant cushiony pads supported by the branches.
The ground underneath a tropical rain forest tends to be fairly open, because only a few kinds of plants can thrive in the low light conditions created by a dense forest canopy. The same light limitation holds true for our forest, and the ground under the Sitka spruce groves is likely to be covered with ferns, mosses, and horsetails.
Epiphytes and ground cover plant species in tropical forests often show a great deal of specialization, and may depend on other forms of life to pollinate them or to spread their seeds. Our Kodiak rain forest plants provide us more of a rearview mirror look through evolutionary history to a time when plants didn't even produce seeds. Those mosses, ferns and horsetails are real primitives, at least in the sense that they have a much longer history on this earth than most of the plants with which we are familiar.
The primitive plants are really only "primitive" in terms of how long they or their relatives have been around. They are certainly not primitive in terms of some elegant adaptations to the Kodiak environment, or in terms of attributes they have developed that also turn out to be useful to humans. Horsetails and ferns, for example, have a range of traditional uses of which the Alutiiq people living in this environment were well aware.
Ferns of the spruce forest floor are edible in the fiddlehead stage, when the tightly coiled fronds just appear above ground. The underground stem may also be prepared as food, and several species have medicinal properties ranging from use as cough medicine to treatment for diarrhea.
Horsetail, also known as scouring rush, is as successful here as anywhere I've seen. I'm certainly not accustomed to thinking of it as a weed species that invades lawns to the extent it does in Kodiak. With its long history and its ability to proliferate, horsetail is one of the most widespread plants in the world. Cooked horsetails are edible when young. They have an array of medicinal uses as well, having been used as an eyewash, a treatment for rheumatism and kidney stones, and a blood coagulant. Because of the silica that they concentrate, the brushy stalks can be used to scour cooking utensils.
All three plant types--mosses, ferns, and horsetails--depend upon moisture for fertilization, and the fog and rain of Kodiak provide moisture aplenty. The plants need to be covered by least a thin film of water through which the male reproductive cells can swim to the female cells. All three types produce tiny spores instead of seeds, and moisture is also important in dispersing the spores away from the parent plants.
Much of what we know about the less primitive flowering plants--those that are more typical of tropical rain forests--seems to be the story of a developing relationship with insects as pollinators. I suspect that the plant-insect relationship may account for some of the differences between tropical rain forests and the Kodiak rain forest. With our short summer seasons, the pollinating insect life just isn't as diverse as that seen in equatorial regions of the earth.
Staking reproductive success on an insect species in the far North may not yield as great an evolutionary payoff as sticking with good old water. Consequently the plant species have taken the conservative route, and the really successful ones are the primitive groups for whom fertilization and dispersal by water has been a successful strategy for many millions of years. As a result of this conservatism, our rain forest provides us a chance to look back in time to expanses of plantlife that have remained virtually unchanged for many millions of years.