求翻译：　　3。有助于环保传统贺卡体积大、纸质好，制造过程中不但需要大量优质木材，而且会严重污染环境。有数据表明，制造4000张贺卡就需要1棵10年生优质树木。使用电子贺卡可以使无数树木免遭涂炭。是什么意思？

3. Contribute to environmental protection bulky traditional greeting cards, paper good, the manufacturing process not only requires a lot of high-quality timber, but will seriously pollute the environment. Data show that made 4000 cards you need a 10-year-high trees. Use of electronic greeting cards