The softwood forests of eastern Europe form part of a zone of vegetation with boreal coniferous trees that extends around the northern hemisphere. At a more southerly latitude and at lower altitudes, one also finds a flourishing range of deciduous forests. This wealth of different kinds of wood forms the basis of a long tradition of timber architecture. Archaeological discoveries confirm the existence of log structures as early as 747 BC in a pre-Slavic early Iron Age settlement in Poland. Extensive remains found in excavations in medieval Novgorod in Russia also reveal widely used forms of timber construction.