sentences:  Under such conditions, the forest enters a state of crisis, being replaced by "piornales" (ciste and broom formations) and thickets "pluvinulares" accompanied at lower levels by Scots pine, often isolated individuals twisted and deformed by the snow.Siliceous mountains such as the Sistema Central, Serra da Estrela, the Sistema Ibérico of the region of Soria, and parts of the Cantabrian mountains, are covered by thickets of "Cytisus purgans" (variously known as "Andorra broom", "Provence broom", or "Spanish gold hardy broom") or Alpine juniper ("Juniperus communis" subsp.