The ecological effects of the cardboard are dual sided. The short answer to your question is yes, cardboard is biodegradable because it is formed by harvesting the plant kingdom. Almost all types of cardboard are obtained from the resources found in plants. Some cardboard is made from recycling paper and pulp. The pulp is largely obtained from plants. The negative side of cardboard manufacturing is that forest is raped the wood is used in creating cardboard which is in great demand in the manufacturing industry. The cardboard is used to form many different types of boxes such as Cardboard display boxes, perfume boxes, cardboard cakeboxes and the list goes on. The piles of earth forests are house to many different life forms and as the forests are being cut and chopped off the different animal and plant species are becoming endangered and extinct. So at one side, the cardboard is biodegradable as the cardboard manufacturers promote and on the other hand, it is threatening many animal and plant species as the environmentalists cry.