#476 Little-leaf Linden (Tilia cordata)

24 June

Not native, but well naturalized. species of tree in the family Malvaceae, native to much of Europe. Other common names include little-leaf or littleleaf linden, small-leaved linden, or traditionally in South East England, pry or pry tree. Its range extends from Britain through mainland Europe to the Caucasus and western Asia. In the south of its range it is restricted to high elevations.

Widely cultivated in North America as a substitute for the native Tilia americana (American linden or basswood) which has a larger leaf, coarser in texture;

#464 Norway Spruce (Picea abies)

12 June

A species of spruce native to Northern, Central and Eastern Europe.[5] It has branchlets that typically hang downwards, and the largest cones of any spruce, 9–17 cm (3+1⁄2–6+3⁄4 in) long. It is very closely related to the Siberian spruce (Picea obovata), which replaces it east of the Ural Mountains, and with which it hybridizes freely. The Norway spruce has a wide distribution for it being planted for its wood, and is the species used as the main Christmas tree in several countries around the world. It was the first gymnosperm to have its genome sequenced.

#461 Green Ash (Fraxinus pennsylvanica)

9 June

Native to eastern and central North America. Green ash is threatened by the emerald ash borer, a beetle introduced accidentally from Asia. Asian ashes have a high tannin content in their leaves which makes them unpalatable to the beetle, while most American species (with the notable exception of blue ash) do not.

#460 Eastern Cottonwood (Populus deltoides)

8 June

Native to North America, growing throughout the eastern, central, and southwestern United States as well as the southern Canadian prairies, the southernmost part of eastern Canada.

It needs bare soil and full sun for successful germination and establishment; in natural conditions, it usually grows near rivers, with mud banks left after floods providing ideal conditions for seedling germination; human soil cultivation has allowed it to increase its range away from such habitats.[8]

Unlike related species such as quaking aspen, it does not propagate through clonal colonies, but will resprout readily when cut down.

The leaves serve as food for caterpillars of various Lepidoptera.

#459 Basswood (Tilia americana)

7 June

A medium-sized to large deciduous tree reaching a height of 18 to 37 m (60 to 120 ft) exceptionally 39 m (128 ft) with a trunk diameter of 1–1.5 m (3–5 ft) at maturity. It grows faster than many North American hardwoods, often twice the annual growth rate of American beech and many birch species. Life expectancy is around 200 years, with flowering and seeding generally occurring between 15 and 100 years, though occasionally seed production may start as early as 8 years.

Dominant in the sugar maple–basswood forest association, which is most common in western Wisconsin and central Minnesota, but occurs as far east as New England and southern Quebec in places that have mesic soil with relatively high pH. It also has minor occurrence in many other forest cover types.

Its flowers provide abundant nectar for insects. The seeds are eaten by chipmunks, mice, and squirrels. Rabbits and voles eat the bark, sometimes girdling young trees. The leaves serve as food for caterpillars of various Lepidoptera (see Lepidoptera which feed on Tilia). The ribbed cocoon maker species Bucculatrix improvisa has not been found on other plants.

This species is particularly susceptible to adult Japanese beetles (an invasive species in North America) that feed on its leaves.

#453 Silver Maple (Acer saccharinum)

1 June

A species of maple native to the eastern and central United States and southeastern Canada. It is one of the most common trees in the United States. Although the silver maple‘s Latin name is similar, it should not be confused with Acer saccharum, the sugar maple. Silver maple’s natural range encompasses most of the eastern US, the midwestern US and southern Canada, that being Southern Ontario and southwestern Quebec.

#452 Swamp White Oak (Quercus bicolor)

31 May

A North American species of medium-sized trees and a common element of America’s north central and northeastern mixed forests. It can survive in a variety of habitats. It forms hybrids with bur oak where they occur together in the wild.

Generally occurs singly in four different forest types: black ash–American elm–red maple, silver maple–American elm, bur oak, and pin oak–sweetgum. Occasionally the swamp white oak is abundant in small areas. It is found within a very wide range of mean annual temperatures from 16 to 4 °C (61 to 39 °F). Extremes in temperature vary from 41 to −34 °C (106 to −29 °F). Average annual precipitation is from 640 to 1,270 mm (25 to 50 in). The frost-free period ranges from 210 days in the southern part of the growing area to 120 days in the northern part. The swamp white oak typically grows on hydromorphic soils. It is not found where flooding is permanent, although it is usually found in broad stream valleys, low-lying fields, and the margins of lakes, ponds, or sloughs. It occupies roughly the same ecological niche as pin oak but is not nearly as abundant. While pin oak seldom lives longer than 100 years; swamp white oak may live up to 300 years.

#451 Common Buckthorn (Rhamnus cathartica)

30 May

A species of small tree in the flowering plant family Rhamnaceae. It is native to Europe, northwest Africa and western Asia, from the central British Isles south to Morocco, and east to Kyrgyzstan.[3][4] It was introduced to North America as an ornamental shrub in the early 19th century or perhaps before, and is now naturalized in the northern half of the continent, and is classified as an invasive plant

Buckthorn is allopathic. Secondary compounds, particularly emodin, have been found in the fruit, leaves, and bark of the plant, and may protect it from insects, herbivores and pathogens. The emodin present in R. cathartica fruit may prevent early consumption, as it is found most in unripe fruits, which allows seeds to reach maturity before being dispersed. Birds and mice significantly avoid eating unripe fruits, and if forced to ingest emodin or unripe fruit, the animals regurgitate the meal or produce loose, watery stools.

Allelopathic effects of exudates from R. cathartica leaf litter, roots, bark, leaves and fruit may reduce germination of other plant species in the soil. Soils in buckthorn-dominated areas are higher in nitrogen and carbon than normal soils, which speeds up decomposition rates of leaf litter. This can result in bare patches of soil being formed and R. cathartica performs well in such disturbed habitats, so this may be adaptive for the setting of its seed.

#377 Manitoba maple (Acer negundo)

17 March 2021

A species of maple native to North America. It is a fast-growing, short-lived tree with opposite, compound leaves. It is sometimes considered a weedy or invasive species, and has been introduced to and naturalized throughout much of the world, including in South America, Australia, New Zealand, South Africa, much of Europe, and parts of Asia. Fast-growing and fairly short-lived tree that grows up to 10–25 m (35–80 ft) tall, with a trunk diameter of 30–50 cm (12–20 in)}, rarely up to 1 m (3.3 ft)} diameter. It often has several trunks and can form impenetrable thickets. The typical lifespan of box elder is only 60 years.

#359 Norway Spruce (Picea abies)

27 February 2021

A species of spruce native to Northern, Central and Eastern Europe.[5] It has branchlets that typically hang downwards, and the largest cones of any spruce, 9–17 cm (3 1⁄2–6 3⁄4 in) long. It is very closely related to the Siberian spruce (Picea obovata), which replaces it east of the Ural Mountains, and with which it hybridises freely. The Norway spruce is widely planted for its wood, and is the species used as the main Christmas tree in several cities around the world. It was the first gymnosperm to have its genome sequenced.