Figure 1.
Start of flowering for hazel and leaf discolouration of English oak since 1951 as indicators for the start and end of the vegetation period
Source: Deutscher Wetterdienst [26] (original language German)
Official websites use .gov
A
.gov website belongs to an official
government organization in the United States.
Secure .gov websites use HTTPS
A lock (
) or https:// means you've safely
connected to the .gov website. Share sensitive
information only on official, secure websites.