PATRIARCH Mr Deng Xiaoping and former president Mr Yang Shangkun have missed the annual tree-planting ceremony in Beijing. However, almost the entire politburo, including disgraced former military strongman General Yang Baibing, showed up for the greening ritual in Biyu Park in the centre of the city. And the media highlighted the core status of party General Secretary Mr Jiang Zemin, who replaced Mr Yang Shangkun as head of state at the recent National People's Congress (NPC). Some diplomatic observers in Beijing believed Mr Deng, 88, did not attend the closing ceremony of the NPC last Wednesday because of ill health. However, they agreed it was a minor problem, and the patriarch was not affected by a serious illness. Mr Deng has not attended the greening ritual, which began 15 years ago, since the spring of 1988. However, it was the first time that Mr Yang, 86, who is noted for his robust health, had missed the ceremony. It is believed the former president wanted to underscore the fact that he had completely retired. The New China News Agency yesterday highlighted the core status of Mr Jiang, when it quoted the party chief as saying it was the fourth year he had taken part in the tree-planting exercise. Mr Jiang, who likes to show off his poetic talents, also quoted the following verses by Mao Zedong: ''Ten thousand willow leaves flutter in the wind; In the motherland, many among the 600 million people are [as virtuous] as the [ancient sage-emperors] Shun and Yao.'' The party boss told officials that the entire nation must persevere with tree-planting work. The NCNA also quoted premier Mr Li Peng as giving Beijing Mayor Mr Li Qiyan a similar instruction. Analysts said the presence of General Yang, who had been relieved of his military positions on the orders of Mr Deng, was a sign that the party wanted to project a facade of unity. The former chief political commissar, who is the younger half-brother of Mr Yang, still has not been given a portfolio in the politburo.