Geoscience Reference
In-Depth Information
Ahuehuete or Montezuma bald cypress (
Taxodium mucronatum
), a widely
distributed riparian species that is considered to be the national tree of Mexico,
has been used to develop the longest tree-ring chronologies in Mexico. In
recent years, over 30 new tree-ring chronologies have been developed or
are in process as part of the CRN03-IAI project. The Douglas-fir chronolo-
gies range between 129 and 604 years, bald cypress between 117 and 1550
years, and pinyon pine (
Pinus cembroides
) over 400 years. Some available
Douglas-fir and bald cypress chronologies are being extended with the use
of cross sections from subfossil wood or logged material. The EW growth
of Douglas-fir trees in Mexico is influenced by dominant climatic condi-
tions in the winter-spring period previous to growth (November to current
season precipitation in northern Mexico is increased by the warm phase of
El Niño/Southern Oscillation (ENSO). On the other hand, the LW width is
affected by the summer precipitation and the monsoon system. Annual ring
width of bald cypress is influenced by the seasonal late spring to summer pre-
cipitation (June-September), explaining 52% of the variance in growth. The
regions of northern and central Mexico have highly limited water resources,
and paleoclimatic reconstructions are essential to understand the hydrocli-
matic variability that characterizes these regions. Determining past climatic
variability is essential to planning proper management strategies for water use,
and tree-ring studies offer the best opportunity to understand this variability
over the last 1000 years.
—J. Villanueva-Diaz, J. Cerano-Paredes, D. Stahle, M. Therrell, M.
Cleaveland, and B.H. Luckman
Box Fig. 7.12
The winter-spring precipitation series reconstructed from an earlywood
Douglas-fir chronology in Chihuahua, Mexico. The reconstruction covers the period
1472-2002
