Tree Rings and Climate: Sharpening the Focus - Dendroclimatology - page 340

enhance understanding of secular variability in large-scale climate patterns prior to
the start of instrumental records.
The North American network of moisture-sensitive trees is now much more
widespread and heavily replicated than that used by Fritts (Meko et al. 1993 ; Cook
et al. 2004b ; Kipfmueller and Salzer, 2010 ) . It extends well into Canada and to
central Mexico (St. George et al. 2009 ; Stahle et al. 1999 , 2007; Villanueva-Diaz
et al. 2007 ) . Major tree-ring networks have been established in South America (see
Villalba et al. Chapter 7 , this volume); Siberia (for example, Vaganov et al. 1996 ;
Esper et al. 2009 ) ; the eastern Mediterranean and North Africa (Touchan et al. 2005 ,
2008); many regions of Europe (for example, Büntgen et al. 2006 ; Helama et al.
2005 ) ; Australasia, especially New Zealand (for example, Fowler et al. 2008 ) and
Tasmania (Cook et al. 2006 ) ; central Asia and China (for example, Jacoby et al.
2003 ; Garfin et al. 2005 ; Yin et al. 2008 ) and the Himalayan region (for example,
Hughes 1992 , 2001 ; Borgaonkar et al. 1996 ; Yadav and Singh 2002 ) ; as well as
the lands around the north Pacific (for example, D'Arrigo et al. 2001 ) . In addition
to these networks, which are based mainly on ring widths, Schweingruber and his
colleagues have established a network of maximum latewood density chronologies
that covers most of the boreal forest and much of the alpine forest of the Northern
Hemisphere, with significant collections outside those regions, too (Schweingruber
and Briffa 1996 ) .
There is still great potential for dendroclimatological network building and for
the intensification and updating of existing networks. Numerous regions are still
radically under sampled; for example, the tropics, including most of Africa; much
of central Asia; and other, smaller pockets, such as European Russia. Data on some
of the major networks were collected in the 1970s and 1980s, and they should be
updated. Given the unusual climate changes in many parts of the globe in recent
decades, tree-ring chronology updating would be particularly valuable in evaluating
potential changes in climate-tree growth responses during this period. It could well
be the case that sample numbers should be greater than has been the case in the
past. It is clearly the case that greatly improved metadata on collection sites and
their topographic, geologic, and ecological context may now be collected by using
modern geospatial technology, and that the interpretation of the ring record would
be greatly improved as a result.
11.9 Growth in the Applications of Dendroclimatology: the 1990s
to Present
Here we consider some exciting new climatic applications of dendrochronology
in the fields of water resources management, wildfire history and risks in western
North America forests, ecological impacts of climatic changes, and the application
of new tools in connection with traditional uses of dendrochronology in archaeolog-
ical work. Similar applications are being made in other regions, and our account is
meant to be indicative, not exhaustive.