referenced on the 2nd page of the document:
Front cover: Northern Hemisphere temperatures were reconstructed for the past 1000 years (up to 1999) using palaeoclimatic records (tree rings, corals, ice cores, lake sediments, etc.), along with historical and long instrumental records. The data are shown as 50-year smoothed differences from the 1961–1990 normal.
Uncertainties are greater in the early part of the millennium (see page 4 for further information). For more details, readers are referred to the PAGES newsletter (Vol. 7, No. 1: March 1999, also available at http://www.pages.unibe.ch) and the National Geophysical Data Center
(Sources of data: P.D. Jones, K.R. Briffa and T.J. Osborn, University of East Anglia, UK; M.E. Mann, University of Virginia, USA; R.S. Bradley, University of Massachusetts, USA; M.K. Hughes, University of Arizona, USA; and the Hadley Centre, The Met. Office)
They refer the reader to this document where on page 8 one finds the hiding of the decline by publishing it.
In the immediate future, work will continue on important statistical issues related to the processing and interpretation of all of the various tree-ring collections. Potential anthropogenic influences on recent tree growth will become an increasingly important focus of the work. Increased tree productivity during the 19th and early 20th centuries and post-1950 declines in tree density trends have recently been identified in our data. The extent, detail and implications of these phenomena have yet to be further explored. Chronology confidence and the expression of climate forcing are most strongly expressed on short (annual to century) timescales. New data processing techniques are exploring...
So the only complaint can be the fact the graph does not differentiate between the proxy and thermometer record.