Central list of listed houses?

I think , subject to correction the answer is no – in terms of printed or accessible documentation.

Some of the larger local authorities have this information regarding buildings on their web sites. Regarding trees, I dont know of any form of listing that is available for general use.

There are a number of volumes being issued listing significant buildings in Irish counties, with photos and lists.
The most recent one to emerge is for Wicklow – These are relatively hard to find outside the largest bookshops in Ireland.

The process of listing buildings is described in the Planning & Development Act 2000 (Part IV Architectural Heritage, Chapter 1 Protected Structures) – see: http://www.irishstatutebook.ie/ZZA30Y2000.html

http://www.buildingsofireland.ie is the website of the National Inventory of Architectural Heritage. Unfortunately, only a few counties have been done so far, buildings detailed online are only a ‘representative sample’ and are not necessarily listed (definitely candidates, though). However, there are good descriptions and photographs of some very interesting buildings.

According to the Green Party, the main instrument for the protection of trees in Ireland is the Forestry Act 1946, with additional protection in the Planning & Development Act 2000. For more info see: http://www.greenparty.ie/en/in_the_dail/agriculture_food/23_nov_04_tree_protection
http://www.irishstatutebook.ie/front.html

Also, South Tipperary County Council has its list of protected trees on the heritage pages of its website, see: http://www.southtippheritage.ie/pport/web/Sitemap/1.2.5.2.7 and its listed buildings are detailed in its Development Plan 2003-2009, see: http://www.southtippheritage.ie/pport/web/Sitemap/1.2.5.2.3

Hope this is helpful.

pure eire