ARBORETUM NEWS (NATURALISTSNOTES)

Conifer Tour

SUNDAY, DECEMBER 4, 2011

Conifers produce seeds in cone-like structures. Most cones are woody with bracts that cover the seeds. Some cones have a berry-like covering. For example, Juniper cones are small, light blue and berry-like. And, yew seeds are enclosed in a fleshy, red, round cone called an “aril”.
Conifers are also called evergreens. They have waxy needles that remain on their branches for a year or more. Their slender needles can be single or clustered. Some conifers such as junipers and arborvitae have needles or leaves that are small, flat and scaly or sharp and prickly. These adaptations help conifers survive dry, cold winter conditions. It seems there is always an exception. Our native larch or tamarack is a conifer but it is not evergreen. It loses its needles in autumn (Deciduous).
This afternoon twenty visitors gathered in the visitor center for our tour featuring Wisconsin’s twelve native conifers. Samples of pine (one of three species), spruce (one of two species), fir, hemlock, juniper (one of three species), arborvitae and larch provided an opportunity for me to point out special features. I gave each participant a copy of a simple needle key to identify conifers before venturing outside on a cloudy 40 degree afternoon with no snow on the ground!
First stop was near the northwest side of the visitor center in front of two conifers. We checked our key and identified them as red cedars (juniperus virginiana). They had two kinds of leaves: short, sharply pointed and/or overlapping scale-like needles. One tree had tiny, yellowish cones that will produce pollen in spring (male). The other (female) had tiny greenish cones and seed cones that were blue and berry-like with a gin odor. Later we saw two other native sun-loving junipers – old field or common (juniperus communis) and creeping or trailing (juniperus horizontalis). These natives tend to turn brown-green in winter.
Next stop was under the stand of eastern white pine (pinus strobus) near the outdoor restrooms. We examined the four-inch long soft needles clustered in bundles of five. We found five-inch long stalked cones that had dropped earlier in the season. Although there were no red pine (pinus resinosa) or jack pine (pinus banksiana) in the stand. Our group learned that red or Norway pine has four to six inch long brittle needles in bundles of two and two-inch round cones. Jack pine needles are one-inch long, twisted and also in bundles of two. Cones are one and a half inch in length, point down and are often in pairs. Some cones open while most remain closed until the heat from a forest fire opens the resinous cone and releases the seeds. Eighty acre stands of 8-20 year old trees are very important for nesting endangered Kirtland’s warblers. Jack pine stands are found mainly in Adams and Jackson County.
Just north of the pines we identified a very beautiful shade-loving eastern or Canada hemlock (tsuga Canadensis). Hemlock needles are not in bundles. They are blunt-tipped, flat and have a very, very tiny leaf stalk. The underside of the half inch to one inch needle has two whitish lines. Tiny round half-inch cones hang down from the feathery drooping branch tips. Hemlock buds and needles are edible and did not poison Socrates. He drank a potion from a plant that belongs to the Parsley family (conium: Greek for Hemlock).
In the same area we noticed many sprawling green shrubs enclosed in wire fences to protect them from browsing deer. Shade tolerant Canada yews (taxus Canadensis) and cultivars have shiny, short, soft blunt-tipped needles. We found small round yellow pollen cones on some shrubs and on others pretty red, fleshy berry-like cups. These cups or arils cover the poisonous seed inside. The needles are also poisonous to eat.
We hiked through Longenecker gardens up to the pinetum located across from Wingra parking lot. The pinetum has a large collection of native and non-native conifers and many cultivars. There we identified our native white spruce (picea glauca). It has a formal, rigid conical form. The half-inch single needles are four-sides and sharply pointed. When they fall, they leave a bump on the twig. Spruce cones hang down and offer seeds to overwintering finches. We did not locate the native black spruce (picea mariana) which is common in northern bogs.
And finally we found our Christmas tree, a balsam fir (abies balsama) with a lovely dark green tapering spire. The fragrant needles are an inch long and are soft, flat and slightly rounded at the tip. The undersides are silvery. The cones are at the top and are upright. They drop their scales and release seeds leaving only a spike.
Many bird species use our Arboretum conifers for food and shelter. Cedar waxwings, overwintering robins and bluebirds eat juniper cones. Chickadees, nuthatches, siskins, crossbills, and other finches from the far north eat conifer seeds especially in winter. Owls use conifers for shelter especially the resident great horned owl and occasionally a migrant saw-whet owl.

Sylvia Marek, Naturalist

Located between Lake Wingra and the West Beltline Highway at 1207 Seminole Highway, the University of Wisconsin-Madison Arboretum features the restored prairies, forests and wetlands of pre-settlement Wisconsin. This 1,260-acre arboretum also houses flowering trees, shrubs and a world-famous lilac collection. Educational tours for groups and the general public, science and nature-based classes for all ages and abilities, and a wide variety of volunteer opportunities for groups, families and individuals are available.