''Picea'' × ''lutzii'' is a hybrid

spruce A spruce is a tree of the genus ''Picea'' (), a genus of about 35 species of coniferous evergreen trees in the family Pinaceae, found in the northern temperate and boreal (taiga) regions of the Earth. ''Picea'' is the sole genus in the subfami ...

tree that is a natural cross between

white spruce White spruce is a common name for several species of spruce (''Picea'') and may refer to: * ''Picea glauca'', native to most of Canada and Alaska with limited populations in the northeastern United States * ''Picea engelmannii'', native to the Ro ...

and

Sitka spruce ''Picea sitchensis'', the Sitka spruce, is a large, coniferous, evergreen tree growing to almost tall, with a trunk diameter at breast height that can exceed 5 m (16 ft). It is by far the largest species of spruce and the fifth-larg ...

occurring where the ranges of the two species overlap in coastal south-central Alaska and coastal British Columbia. Its common name is Lutz spruce. Its morphology is intermediate between the two parent species, the maritime Sitka spruce and the white spruce of dryer climates further inland. In addition to the parent spruces it shares its ecosystem with ''

Tsuga heterophylla ''Tsuga heterophylla'', the western hemlock or western hemlock-spruce, is a species of hemlock native to the west coast of North America, with its northwestern limit on the Kenai Peninsula, Alaska, and its southeastern limit in northern Sonoma ...

'' and '' T. mertensiana''. The tree was named for Harold John Lutz, a scientist who specialized in forest soils and worked briefly for the

United States Forest Service The United States Forest Service (USFS) is an agency of the U.S. Department of Agriculture that administers the nation's 154 national forests and 20 national grasslands. The Forest Service manages of land. Major divisions of the agency inc ...

in Alaska where he collected the material used to describe the hybrid. A Lutz spruce from Alaska's

Chugach National Forest The Chugach National Forest is a United States National Forest in south central Alaska. Covering portions of Prince William Sound, the Kenai Peninsula and the Copper River Delta, it was formed in 1907 from part of a larger forest reserve. The Ch ...

was selected in 2015 for the

Capitol Christmas Tree The Capitol Christmas Tree (formerly the Capitol Holiday Tree) is the decorated tree that is erected annually on the West Front Lawn of the United States Capitol, in Washington, D.C., to celebrate the Christmas holiday season. The selection, in ...

. This is the first Capitol Tree that has come from the state of Alaska. Lutz's spruce grows as tall as 30 meters in height, and it is a generally symmetrical tree with open and downward bowing branches. While its needles are sharp like the Sitka spruce, they are not as "stiff" and, therefore, less "prickly." The seed cones closely resemble those of the Sitka spruce but are smaller and with the rounded tops of white spruce cones. Between 1987 and 2000 the largest known epidemic of spruce bark beetle (''

Dendroctonus rufipennis ''Dendroctonus rufipennis'', the spruce beetle, is a species of bark beetle native to British Columbia, Newfoundland and Labrador, Nova Scotia, Ontario, Quebec, Northern Manitoba, the Yukon, Colorado, Wyoming, Montana, and Maine. They are known t ...

'') caused the death of 90% of white, Sitka, and hybrid Lutz spruce, almost all of the mature spruce trees, in a 3.2 million acre forest in the Kenai Peninsula and Copper River. The spruce bark beetle is a part of the native ecosystem, mainly hosted by the white spruce of the dryer interior, in south-central Alaska where the tree loss occurred in apparently healthy old growth forest. One theory about the decimation of trees is that warmer spring and summer temperatures have allowed the beetles an annual reproductive cycle, shortened from every two to three years, while warmer winter temperatures have increased the number of beetles that live through winter to reproduce in spring. In addition to increased temperatures, increased aridity in the region has created dryer forests lowering the production of sap, a barrier defense against insect and fungal pests, in the spruces. Lutz spruces, like its primary host, the white spruce, are more susceptible than

and

black spruce ''Picea mariana'', the black spruce, is a North American species of spruce tree in the pine family. It is widespread across Canada, found in all 10 provinces and all 3 territories. It is the official tree of the province of Newfoundland and Labra ...

to bark beetle damage and suffer a higher mortality rate when infected."Classification of spruce beetle hazard in Lutz spruce (''Picea'' × ''lutzii'') stands on the Kenai Peninsula Alaska"
, by K. M. Reynolds and E. H. Holsten, in ''Canadian Journal of Forest Research,'' 24:5, p 1015-1021, 1994, at

ResearchGate ResearchGate is a European commercial social networking site for scientists and researchers to share papers, ask and answer questions, and find collaborators. According to a 2014 study by ''Nature'' and a 2016 article in ''Times Higher Education'' ...

References

External link

{{DEFAULTSORT:Picea lutzii lutzii Hybrid plants Flora of Alaska Flora of British Columbia Flora without expected TNC conservation status