{"id":2954,"date":"2011-09-16T06:12:13","date_gmt":"2011-09-15T20:12:13","guid":{"rendered":"https:\/\/scienceillustrated.com.au\/blog\/?p=2954"},"modified":"2012-03-21T09:29:22","modified_gmt":"2012-03-20T22:29:22","slug":"dead-shrubs-reveal-past-climate-changes","status":"publish","type":"post","link":"https:\/\/scienceillustrated.com.au\/blog\/nature\/dead-shrubs-reveal-past-climate-changes\/","title":{"rendered":"Dead shrubs reveal past climate changes"},"content":{"rendered":"
\"\"<\/p>\n

Mountain plum pine are found in the high alpine areas. Image: Shutterstock<\/p>\n<\/div>\n

The growth rings of alpine shrubs can provide a clue to past climatic conditions.<\/strong><\/p>\n

Mountain plum pines (Podocarpus lawrencei<\/a>) are found in the Australian Alps and can live for up to 600 years, with an annual growth rate of less than one millimetre. In 2003 and 2006 bushfires in the alpine areas led to the death of a large number of these shrubs, which regenerate from seeds in the soil.<\/p>\n

Many of the shrubs in the Alps were over 400 years old and form part of the habitat of the endangered pygmy possum, so scientists were unable to take samples from them. But the large numbers of dead mountain plum pines enabled scientists from the Australian National University<\/a> (ANU) and the NSW Office of Environment and Heritage<\/a> to investigate the growth rings of these shrubs.<\/p>\n

“That opened the opportunity for us to finally go to these stands of mountain plum pines and take samples from them,”\u009d said Dr Brookhouse from ANU. “We have been interested in it for a long time, but it just hasn’t been possible.”\u009d<\/p>\n

The initial samples were taken from stands near Perisher and Schlinks Pass in Kosciusko National Park. The researchers have since collected samples from across the Alps, including Mt Buller, Mt Hotham, the Bogong High Plains and the Jagungal Wilderness, to determine whether the climate signals were consistent across the region.<\/p>\n

The samples are sanded with six different grades of sandpaper to remove any scratches that might obscure the growth rings. They are then scanned and analysed with measurement software, with the sample physically present under a microscope to enable cross-referencing.<\/p>\n

Colder years can result in a lack of growth and hence missing growth rings, so the samples are cross-dated to correlate the growth rings with calendar years and develop a chronological record. “(It’s) absolutely critical for climate analysis- you can’t analyse climate if you haven’t pinpointed the year,”\u009d Dr Brookhouse said.<\/p>\n

Mountain plum pines are very sensitive to temperature, making them a key source of long term climate data and providing a context for what will happen to alpine vegetation in the event of climate change. “The data is an actual measure of growth in a plant in the alpine area, so we can see how this plant responds to climate change.”\u009d<\/p>\n

The researchers have also identified deep snow years (from known records) from the growth rings and can reconstruct past fire events from plant regeneration. “We have a dataset that allows us to put any current changes into a broader perspective.”\u009d<\/p>\n

The records constructed from these samples extend back to 1888, but Dr Brookhouse said they are “definitely aiming to measure back 400 years.”\u009d<\/p>\n","protected":false},"excerpt":{"rendered":"

The growth rings of alpine shrubs can provide a clue to past climatic conditions.<\/p>\n","protected":false},"author":2,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[84,64,45,6,49,8],"tags":[],"class_list":["post-2954","post","type-post","status-publish","format-standard","hentry","category-climate","category-ecology","category-environment","category-nature","category-palaeontology","category-science"],"aioseo_notices":[],"_links":{"self":[{"href":"https:\/\/scienceillustrated.com.au\/blog\/wp-json\/wp\/v2\/posts\/2954"}],"collection":[{"href":"https:\/\/scienceillustrated.com.au\/blog\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/scienceillustrated.com.au\/blog\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/scienceillustrated.com.au\/blog\/wp-json\/wp\/v2\/users\/2"}],"replies":[{"embeddable":true,"href":"https:\/\/scienceillustrated.com.au\/blog\/wp-json\/wp\/v2\/comments?post=2954"}],"version-history":[{"count":4,"href":"https:\/\/scienceillustrated.com.au\/blog\/wp-json\/wp\/v2\/posts\/2954\/revisions"}],"predecessor-version":[{"id":2961,"href":"https:\/\/scienceillustrated.com.au\/blog\/wp-json\/wp\/v2\/posts\/2954\/revisions\/2961"}],"wp:attachment":[{"href":"https:\/\/scienceillustrated.com.au\/blog\/wp-json\/wp\/v2\/media?parent=2954"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/scienceillustrated.com.au\/blog\/wp-json\/wp\/v2\/categories?post=2954"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/scienceillustrated.com.au\/blog\/wp-json\/wp\/v2\/tags?post=2954"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}