A quick search online indicates that The Wicker Tree is in eminent danger of being buried in a sea of middling to bad notices, and that is a real shame, for while the film is certainly flawed, it is nevertheless a unique and valuable piece of storytelling.
First, we must do away with the looming shadow of its predecessor: The Wicker Man it is most decidedly not - but then, what is? If one judges The Wicker Tree on its paucity of similarities to its spiritual forbear, then one will naturally consider it a failure simply because it was never intended to faithfully recreate the original film in the first place. The Wicker Tree, rather, is a black comedy/commentary painted in bold strokes that deals not in the nature of sacrifice, but in the nature of the various roles we play throughout our lives, and whether we are guided by or can avoid not faith, but fate.
Young former country-pop singer Beth Boothby (Brittania Nicol) has rejected her debauched, secular and trashy (literally, check the lyrics) music and image to embrace evangelical Christianity and folksier, mostly religious tunes. Together with her cowboy fiancee Steve (Henry Garrett) and their matching purity rings, she's on her way to Scotland (a country that was all but entirely Christian before North America was even discovered) to witness to those kilted heathens who - horror of horrors! - don't even believe in angels.
(Side note: that most critics seem to have missed the fact that The Wicker Tree is a black comedy playing on and with broad stereotypes even after having the above setup literally spelled out for them in the first ten minutes of the film is beyond me.)
It is in Scotland that Beth meets Lord Lachlan Morrison and his wife, Lady Delia (Graham McTavish and the criminally underused Jacqueline Leonard), and the wheel of fate is set inexorably in motion. Beth and Steve demonstrate time and again that they are not only naive, but also not intellectually equipped to engage in matters of philosophy or any faith other than their own, and so both fail utterly to sense the danger surrounding them. Interestingly, despite their intellectual disparity, Lachlan has an inner struggle that almost parallels Beth's - against who they were, who they are, and what they desire to be. While Beth struggles to live down her ignoble past, Lachlan faces questions about the nature and sincerity of his faith in the present, and rightly so, for it seems that, as owner of the local nuclear plant, he is fully cognizant of the fact that it is most likely his own business that has caused local birth rates to drop precipitously, though publicly he insists that he and his followers need only find the right sacrifice to solve their reproductive ills.
Betrayals of self, faith and others like these abound in The Wicker Tree. Steve is easily lead astray by local seductress Lolly (a stunning Honeysuckle Weeks), convincing him that he has failed both as man and a Christian. Lolly in turn attempts not once but twice to betray her fellow cultists while Lachlan all but admits to his wife his faith has abandoned him. It is Beth, however, who finally demonstrates most savagely that fate, not faith, rules this universe, as she betrays her own evangelical ideals in a moment of anger and despair.
Philosophical undercurrents aside, another question on a lot of minds seems to be whether or not this is a standard "horror" film. The answer is...complicated. It is at least as much a horror film as The Wicker Man, though by today's standards, neither film is stictly "horror" at all. The Wicker Tree does have horror elements, but also comedy elements and musical elements - more important than what genre to slot it into is that it is not always successful at blending all those genres, and that is in part why I concede that it is flawed.
Foremost among these flaws? It is unfortunately true that casting two unknowns in the lead roles was a gamble that did not entirely pay off. Nicol and Garrett both give some truly stilted line readings, but these moments in no way overshadow the film as whole. One would have liked to have seen the aforementioned parallels between Beth and Lachlan better defined, but they and other subplots remain underutilized. Finally, the shoestring budget is unfortunately very much evident in some of the cinematography and editing, but save for one scene in which Steve seems to doing some kind one-man see-saw act, the issues are minor and not overly distracting.
To sum up: Imperfect, but with a unique story and philosophical core. Put The Wicker Man out of your mind and give The Wicker Tree a shot strictly on its own merits. You will almost certainly find something to like.